Nuclear Physics Seminars History

Nuclear
Tuesday, April 28, 2020
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, April 21, 2020
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, March 31, 2020
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, March 24, 2020
3:30 PM
Physics Building, Room 204

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RESERVED
Nuclear
Tuesday, March 17, 2020
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, March 10, 2020
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, March 3, 2020
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, February 25, 2020
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, February 18, 2020
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, February 11, 2020
3:30 PM
Physics Building, Room 204

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"The Lead Radius Experiment (PRex-II)"


Siyu Jian , University of Virginia - Department of Physics
[Host: Nilanga Liyanage]
ABSTRACT:

The RMS radius of the neutron distribution in a heavy nucleus RN provides an important test of nuclear theory. Furthermore RN is used in the determination of the density dependence of symmetry energy of neutron rich matter; this dependence is an important input in neutron star structure, heavy iron collision and atomic parity violation experiment calculations. In the past hadron scattering experiments with with pion, proton or anti-proton beams have been used to determine the neutron radii of heavy nuclei. However, these measurements suffer from uncertainties associated with the probe particle and the target nucleus. Electron scattering provides a model independent probe of nuclear radii. However, in electron scattering, the measurement of neutron distribution in a nucleus is much harder than the measurement of the proton distribution since the neutron is uncharged. Because the neutron weak charge is much large than that of the proton, PRex-II used the parity violating weak neutral interaction to probe the neutron distribution in the 208Pb nucleus, thus measuring the RMS neutron radius with high accuracy. The PRex-II experiment was performed from June to September 2019 in Jefferson lab experimental hall A using the High Resolution Spectrometer (HRS) pair. This seminar presents the details the PRex-II experiment as well as the preliminary results from HRS Optics calibration measurements and from the Gas Electron Multiplier (GEM) detectors used for obtaining high rate calibration data.
 

Nuclear
Tuesday, February 4, 2020
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, January 28, 2020
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, January 21, 2020
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, January 14, 2020
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, December 3, 2019
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, November 26, 2019
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, November 19, 2019
3:30 PM
Physics Building, Room 204

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"A new comparison of the F2A/F2p and F2A/F2n structure function ratios "


Narbe Kalantarian , Virginian Union University and Jefferson Lab
[Host: Simonetta Liuti]
ABSTRACT:

Using electron scattering data from SLAC E139 and muon scattering data from NMC in the DIS region, we determine the F2A/F2p and F2A/F2n structure function ratios, spanning 0.07 < xB < 0.7 and 1 < Q2 < 200 GeV/c2 and 0.006 < xB < 0.6 and 1 < Q2 < 55 GeV/c2, respectively. This region is of particular relevance to studies of EMC Effect. Assuming no Q2 dependence, we compare the structure function ratios for isoscalar nuclei and study non-isoscalar nuclei with the possibility to look for flavor dependence. This talk will present the results of the mentioned ratios for isoscalar nuclei using the new F2n global data from the CTEQ-JLab Collaboration.

Nuclear
Tuesday, November 12, 2019
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, November 5, 2019
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, October 29, 2019
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, October 22, 2019
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, October 15, 2019
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, October 8, 2019
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, October 1, 2019
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, September 24, 2019
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, September 17, 2019
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, September 10, 2019
3:30 PM
Physics Building, Room 204

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"The Muon g-2 Experiment at Fermilab"


Chris Hong , University of Virginia - Physics
[Host: Dinko Pocanic]
ABSTRACT:

The Muon g-2 experiment at Fermilab (E989) is addressing the known, but not yet understood incompleteness of the Standard Model (SM) theory by measuring the anomalous magnetic dipole moment, am, defined as (gm-2)/2. To be able to test the SM predictions, the experiment aims to reach the precision of 0.14 ppm. At Fermilab a intense proton beam is passed through a target where pions are produced; after a long delay virtually all pions decay into muons, which are stored in a muon storage ring. Evaluation of am requires the measurement of the muon spin precession frequency in the storage ring and, of the mean magnetic field the stored muons experience. I will introduce the experiment, its basic measurement techniques, and will focus on the magnetic field measurement, my thesis topic. The basic method relies on the free induction decay (FID) signals from NMR probes. Of particular interest is understanding and quantifying the possible interference between the electrostatic beam focusing quadrupoles and the FID signals in the 378 "fixed" NMR probes mounted all around the storage ring.

Nuclear
Tuesday, September 3, 2019
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, August 27, 2019
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, April 30, 2019
3:30 PM
Physics Building, Room 204

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ABSTRACT:

E12-10-002 ran in Hall C in Spring of 2018 for about 3 weeks with the goal of extracting cross sections for H(e,e') and D(e,e') reactions in the deep inelastic and resonance region regimes. Our data cover a broad range in Bjorken x and we reached Q^2 values as high as 14 GeV^2. E12-10-002 will have an impact on a wide range of physics topics like Parton Distribution Functions extractions, Quark-Hadron Duality studies, F2_neutron/F2_proton at large x, modeling of H(e,e') and D(e,e') processes and moments of the F2 structure function.

In this talk I will summarize the physics motivation for running the experiment and I will also highlight the sinuous path to getting precision cross sections from measurements done with a brand new spectrometer (Super High Momentum Spectrometer) and a new data acquisition system.

Special Nuclear Seminar


Thursday, April 25, 2019
3:30 PM
Physics Building, Room 204

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"Wigner Distributions"


Dr. Matthias Burkardt , New Mexico State University
[Host: Simonetta Liuti]
ABSTRACT:

An overview of the physics of Wigner Distributions will be presented within the context of the recently established  Jefferson Lab Center for Nuclear Femtography.

SLIDESHOW:
Nuclear
Tuesday, April 23, 2019
3:30 PM
Physics Building, Room 204

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"Extraction of Observables from Deeply Virtual Electron Proton Scattering Experiments"


Brandon Kriesten , University of Virginia - Physics
[Host: Simonetta Liuti]
ABSTRACT:

Imaging the 3D partonic structure of the nucleon is a fundamental goal of every major nuclear experimental program, including the EIC. Ji first proposed Deeply Virtual Compton Scattering (DVCS) as a probe for understanding the spatial distribution of the partons by fourier transform of the exchanged momentum transfer between the initial and final proton. The extraction of observables from Deeply Virtual Exclusive Reactions in a clear and concise formalism, such that the various twist components and angular dependencies can be untangled, is key. We present a completely covariant description of the DVCS process that can be extended to any kinematics, either fixed target or collider. In our helicity formalism, we extract our observables such that the dependence on Q2 is clear. We can separate kinematic twist, characterized by subleading dependence on 1/Q2, from the dynamic twist, given by the Q2 suppression and azimuthal angle ɸ. Since the higher twist terms are characterized by their dependence on ɸ, it is important to understand the angular contribution arising from the kinematic variables and separate it from the characteristic angular dependence of the higher twist terms. The extension to other Deeply Virtual Exclusive Reactions, such as TCS, is in progress. From our formalism, one can extract observables important in understanding the physical properties of the proton such as the angular momentum of the quarks and gluons inside of the proton.

Nuclear
Tuesday, April 16, 2019
3:30 PM
Physics Building, Room 204

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"The GDH Integrand of the Deuteron"


Matthew Roberts , University of Virginia - Physics
[Host: Blaine Norum]
ABSTRACT:

The ultimate goal of my research is to measure for photons between 8 and 20 MeV using a frozen-spin target originally constructed at CERN in the mid 1970’s. The goal is to 1) look for a dibaryon state of the deuteron and to 2) investigate suspected deviations of the Gerasimov-Drell-Hearn integrand. In order to make sure we are as prepared as possible, we practice operation of the target in our lab. The primary goal of these practice runs or “cooldowns” is to achieve the ideal ratio of Helium-3 and Helium-4 in the target chamber of our dilution refrigerator in order to get it down to the coldest temperature possible and then to measure the polarization of the target. However, we have hit a few bumps along the way, and cannot currently do cooldowns due to our dilution fridge leaking. The primary focus of my talk will be on the steps we have taken to fix our fridge and get back to doing proper cooldowns.

Nuclear
Tuesday, April 9, 2019
3:30 PM
Physics Building, Room 204

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"Source Studies and Polarimetry for Upcoming PREX-II and CREX Experiments "


Sachinthani Premathilake , University of Virginia - Physics
[Host: Kent Paschke]
ABSTRACT:

Parity-violating electron scattering provides a clean probe of neutron densities that is model independent and free from most of the strong interaction uncertainties. The PREX-II and CREX experiments at Jefferson lab aim to measure the nucleon skin thickness in 208Pb and 48Ca via parity violating electroweak asymmetry in the elastic scattering of left and right polarized electrons. These measurement from Pb and Ca are sensitive to the existence of this neutron skin and it will provide information on nuclear structure. Knowledge of difference in proton and neutron radius or an effective neutron skin thickness is required in order to calibrate the equation of state for neutron rich nuclear matter.

I will discuss how we are getting ready for the upcoming 2019 runs of both experiments, especially focused on source studies and polarimetry studies.

Nuclear
Tuesday, April 2, 2019
3:30 PM
Physics Building, Room 204

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"Probing neutron spin framework with polarized 3He"


Christopher Jantzi , University of Virginia - Physics
[Host: Gordon Cates]
ABSTRACT:

Two types of functions used to describe the electromagnetic structure of nucleons include “form factors”, which describe the spatial distribution of charge and magnetism within the nucleon, and “structure functions”, which describe their longitudinal momentum distribution. We explore form factors by exclusive scattering of high energy leptons with the nucleus or focusing on elastic channels in our analysis; we explore structure functions by inclusive scattering with the nucleus. When exploring the electromagnetic structure of the neutron, 3He is an ideal target for quasi-elastic scattering because the proton-proton wave-function is dominated by the spin-zero, S-state (by approximately 90%). Thus, scattering leptons from a polarized 3He target is a reasonable approximation to scattering from a polarized, free neutron.

My talk will focus on the polarizable 3He targets used in two experiments at Jefferson National Laboratory: one experiment explores the neutron electric form factor, GE­n, and the other experiment explores the neutron structure function, A1n. I will discuss my work in the filling and characterization of these targets as well as optimizing these targets for future experiments at higher beam energies.

Nuclear
Tuesday, March 26, 2019
3:30 PM
Physics Building, Room 204

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"Simulations and Polarimetry for the PREX-II and CREX Experiments"


Adam Zec , University of Virginia - Physics
[Host: Kent Paschke]
ABSTRACT:

The PREX-II and CREX experiments are both parity-violating electron scattering experiments which seek to probe the weak form factor of the nuclei of 208Pb and 48Ca respectively by measuring an asymmetry between the scattering of left- and right-handed electrons. These experiments seek to constrain models of nuclear theory by measuring the radius of a “neutron skin” in neutron-rich nuclei. There are a number of experimental challenges associated with these very high luminosity, high precision measurements. I will discuss how we will meet these challenges in the upcoming 2019 runs of both experiments.

Nuclear
Tuesday, March 19, 2019
3:30 PM
Physics Building, Room 204

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ABSTRACT:

TBA

Nuclear
Tuesday, March 5, 2019
3:30 PM
Physics Building, Room 204

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Special Joint Nuclear and High Energy Seminar


Thursday, February 28, 2019
2:00 PM
Physics Building, Room 204

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"A New QCD Facility at the M2 beam line of the CERN SPS (COMPASS++/AMBER)"


Oleg Denisov , COMPASS experiment
[Host: Dustin Keller]
ABSTRACT:

Possibility to use high intensity secondary beams at the SPS M2 beam
line in combination with the world’s largest polarized target, liquid hydrogen,
liquid deuterium and various nuclear targets create a unique opportunity
for universal experimental facility to study previously unexplored aspects
of meson and nucleon structure, QCD dynamics and hadron spectroscopy. 

High intensity hadron (pion dominated) beams already made COMPASS the
world leading facility for hadron spectroscopy and  hadron structure
study through Drell-Yan production of di-muon pairs. High intensity
muon beams, previously used for unique semi-inclusive and exclusive
hard scattering programs, make possible proton radius measurement in
muon-proton elastic scattering and further development of polarized
exclusive hard scattering program.
  
Upgrades of the M2 beam line resulting in high intensity RF-separated
anti-proton- and kaon-beams would greatly expand the horizon of experimental
possibilities at CERN: hadron spectroscopy with kaon beam, studies
of transverse momentum dependent quark structure for protons, pions and
kaons, precise studies of nuclear effects and for the first time measurements
of kaon quark—gluon substructure.

Nuclear
Tuesday, February 26, 2019
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, February 19, 2019
3:30 PM
Physics Building, Room 204

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"Probing Polarized Nuclei to Explore the Structure of Matter"


James Maxwell , Jefferson Lab
[Host: Kent Paschke]
ABSTRACT:

Since the failure of classical mechanics at subatomic scales, understanding the spin of fundamental particles has been central to the investigation of the most basic workings of matter. Beyond a key property for study, spin has become an indispensable instrument for experimental discovery in the form of polarized beam sources and scattering targets. As physicists have turned from the successful description of the weakly bound, perturbative regime of QCD toward unraveling the mysteries of confinement and the glue, ever-improving polarized tools are as crucial as ever. This talk will give an overview these tools, emphasizing solid polarized targets for leptonic probes of QCD, covering their operation, development and upcoming experimental use. With the promise of a nuclear physics facility for e-N collisions on the horizon, I will discuss a new technique to produce a polarized He3 beam source. Finally, a new search for exotic glue in the nucleus using polarized targets and sources will be introduced.

Nuclear
Tuesday, February 12, 2019
3:30 PM
Physics Building, Room 204

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Reserve
[Host: Kent Paschke]
Special Nuclear Seminar


Thursday, February 7, 2019
3:30 PM
Physics Building, Room 204

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"UVA Solid State Polarized Target Program"


Dustin Keller , University of Virginia
[Host: Kent Paschke]
ABSTRACT:

The UVA solid polarized target group has been a hub for scattering experiment
polarized target research for the last 30 years.  Solid state polarized targets provide
high polarization and high density for many types of fixed targets employed by nuclear
labs worldwide.  Dynamic nuclear polarization and other RF techniques are
used to enhance the polarization of the cryogenically cooled solid
material to improve the figure of merit of the experiment.  An overview of
the technology and techniques is given with an emphasis on recent
developments.  Some future experiments are discussed providing examples of
implementation of this research which make it possible to access many spin-dependent
degrees of freedom used to test fundamental prediction of QCD.


 

Nuclear
Tuesday, February 5, 2019
3:30 PM
Physics Building, Room 204

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Nuclear
Monday, February 4, 2019
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, January 29, 2019
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, January 22, 2019
3:30 PM
Physics Building, Room 204

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RESERVED
Nuclear
Tuesday, January 15, 2019
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, December 4, 2018
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, November 27, 2018
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, November 20, 2018
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, November 13, 2018
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, November 6, 2018
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, October 30, 2018
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, October 23, 2018
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, October 16, 2018
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, October 9, 2018
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, October 2, 2018
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, September 25, 2018
3:30 PM
Physics Building, Room 204

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RESERVED
Nuclear
Tuesday, September 18, 2018
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, September 11, 2018
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, September 4, 2018
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, August 28, 2018
3:30 PM
Physics Building, Room 204

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RESERVED
Nuclear
Tuesday, May 1, 2018
3:30 PM
Physics Building, Room 204

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"The Search for Color Transparency at 12 GeV at JLab"


John Matter , UVA- Department of Physics
[Host: Nilanga Liyanage]
ABSTRACT:

Color Transparency (CT) refers to a prediction of QCD that at high momentum transfer Q^2, a system of quarks, each of which would normally interact very strongly with nuclear matter, could form a small color-neutral object whose compact transverse size would be maintained for some distance, passing through the nuclear medium undisturbed. A clear signature of CT would be a dramatic rise in nuclear transparency with increasing Q^2. The existence of CT would contradict traditional Glauber multiple scattering theory in its domain of validity, which predicts constant nuclear transparency. CT is also a prerequisite to the validity of QCD factorization theorems, which provide access to generalized parton distributions that contain information about the transverse and angular momenta carried by quarks in nucleons. The E12-06-107 experiment in JLab's Hall C will look for a signature of CT in electron-proton scattering with carbon-12 and liquid hydrogen targets. Data for Q^2 between 8 and 14 GeV^2 were taken in early 2018 in JLab's Hall C, a range over which nuclear transparency should differ appreciably from conventional Glauber calculations.

 

Nuclear
Tuesday, April 24, 2018
3:30 PM
Physics Building, Room 204

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ABSTRACT:

I will share two applications of spin-polarized noble gas imaging using magnetic resonant imaging. To date, self-sustained fusion energy production has not been achieved since the energy spent in containing the plasma favorable for fusion reaction surpasses the energy outcome. Spin-polarized fusion (SPF) promises a 50% boost in fusion cross section between deuterium and tritium (or He-3). However, SPF has not been experimentally tested in a reactor for several logistical challenges related to delivery of polarized fuels to the plasma.

In collaboration with General Atomics and JLab, we propose to optimize and measure polarization survival of spin-polarized He-3 during permeation into polymer-shelled inertial-confinement fusion (ICF) pellets, a crucial step toward achieving SPF. Granted that adequate polarization survival into the pellets is achieved, the SPF reaction of D and 3He will be tested in the General Atomics D-III D Tokamak which would be the very first experimental demonstration of SPF in a fusion energy reactor.

CT has been the golden standard imaging technique to characterize and quantify emphysema, however, it exposes the body to ionizing radiation. An alternative image based method of characterizing emphysematous lung tissue is by having the patient inhale spin-polarized noble gas (He-3 or Xe-129) and image the gas inside the lungs. Since diffusion of the gas molecules inside the lungs are constrained by the microstructure of the lungs, how far gas molecules travel can tell us about regional tissue destruction due to emphysema. Here we introduce a novel method of defining emphysema index based on apparent diffusion coefficient maps acquired using a diffusion-weighted MRI pulse sequence.

Nuclear
Tuesday, April 17, 2018
3:30 PM
Physics Building, Room 204

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"Polarized Electron Source for the MOLLER Experiment"


Caryn Palatchi , UVA - Department of Physics
[Host: Kent Paschke]
ABSTRACT:

The MOLLER experiment at Jefferson Laboratory will be part of a new generation of ultra high precision electroweak experiments. It will measure the Moller (electron-electron scattering) parity-violating asymmetry, providing an unprecedented precision on the electroweak mixing angle. To achieve such small uncertainties, innovative techniques in the electron source are required to switch the beam helicity more quickly than previously achievable. A key technology is the Pockels cell in the laser optics of the polarized electron source. RTP crystals have been demonstrated to achieve almost an order of magnitude faster transition times than commonly used KD*P crystal cells and are promising for the future Moller Experiment. 

Nuclear
Tuesday, April 10, 2018
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, April 3, 2018
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, March 27, 2018
3:30 PM
Physics Building, Room 204

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Available
Nuclear
Tuesday, March 20, 2018
3:30 PM
Physics Building, Room 204

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Reserved for HEP Seminar
[Host: Craig Dukes]
Nuclear
Tuesday, March 13, 2018
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, February 27, 2018
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, February 20, 2018
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, February 13, 2018
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, February 6, 2018
3:30 PM
Physics Building, Room 204

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RESERVED
Nuclear
Tuesday, January 30, 2018
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, January 23, 2018
3:30 PM
Physics Building, Room 204

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[Host: ]
Nuclear
Tuesday, December 5, 2017
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, November 28, 2017
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, November 21, 2017
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, November 14, 2017
3:30 PM
Physics Building, Room 204

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RESERVED
Special Nuclear/ High Energy Seminar


Tuesday, November 7, 2017
3:30 PM
Physics Building, Room 204

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"The Hunt for Lepton Number Violation: A Cold-Hearted Approach"


Tommy O'Donnell , Virginia Tech
[Host: Craig Group]
ABSTRACT:

The CUORE experiment, a ton-scale cryogenic bolometer array, recently began operation at the Laboratori Nazionali del Gran Sasso in Italy. The array represents a signi cant advancement in this technology and exceeds the size of previous experiments of this type by more than ten fold. In this talk we give an overview of the design and performance of the detector and present the results from a high-sensitivity search for a lepton-number{violating process: 130Te neutrinoless double-beta decay.

Nuclear
Tuesday, October 31, 2017
3:30 PM
Physics Building, Room 204

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"TBA"


TBA
[Host: Stefan Baessler]
Special Nuclear Seminar


Monday, October 30, 2017
3:30 PM
Physics Building, Room 204

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"Taming the nuclear beta decay Hydra: One theoretical head at a time"


Leendert Hayen , KU Leuven
[Host: Stefan Baessler]
ABSTRACT:

The study of nuclear beta decay has been at the forefront of our current understanding of the physical landscape, and continues to play an essential role in the search for beyond Standard Model physics. In order to separate the wheat from the chaff of the myriad possible theoretical extensions, a reliable estimate of the Standard Model contribution is indispensable. Recently, the description of the allowed beta spectrum shape was revisited and extended in order to tackle these challenges. Besides the study of the fundamental nature of the weak interaction, the beta spectrum shape is an essential ingredient in several outstanding problems in particle physics, such as the reactor antineutrino anomaly. We will provide an overview of the current state-of-the-art and its challenges, and discuss its implications on the reactor anomaly and behavior of geo-neutrinos.

SLIDESHOW:
Nuclear
Tuesday, October 24, 2017
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, October 17, 2017
3:30 PM
Physics Building, Room 204

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RESERVED
Nuclear
Tuesday, October 10, 2017
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, September 26, 2017
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, September 19, 2017
3:30 PM
Physics Building, Room 204

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RESERVED
Nuclear
Tuesday, September 12, 2017
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, September 5, 2017
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, August 29, 2017
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, August 22, 2017
3:30 PM
Physics Building, Room 204

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RESERVED
Nuclear
Wednesday, July 12, 2017
3:30 PM
Physics Building, Room 313

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"Polarization Observables in Wide-Angle Compton Scattering at large s, −t and −u"


David J. Hamilton , University of Glasgow
[Host: Donal Day and Dustin Keller]
Nuclear
Wednesday, May 17, 2017
2:30 PM
Physics Building, Room 313

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"Measurement of the Spectral Function of Argon Through the (e,e'p) Reaction at Jefferson Lab"


Dan Abrams , University of Virginia - Department of Physics
[Host: Donal Day]
Nuclear
Tuesday, May 2, 2017
3:30 PM
Physics Building, Room 204

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RESERVED
Nuclear
Tuesday, April 25, 2017
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, April 18, 2017
3:30 PM
Physics Building, Room 204

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"PRad experiment at Jefferson Lab"


Xinzhan Bai , UVA- Physics Department
[Host: Nilanga Liyanage]
ABSTRACT:

The proton charge radius is one of the most fundamental parameter in physics. Precise knowledge of its value is critically important in various physics field.

Recent high precision measurement of proton radius using the spectroscopy method of muonic hydrogen atom demonstrated a much smaller value, which is more than 5 standard deviations away from the widely accepted CODATA value. This fact triggered the well known “proton charge radius puzzle”.  In order to investigate this puzzle, the PRad experiment was performed in 2016 at Jefferson Lab in Hall B. This experiment aims to extract the electric form factor in an unprecedented small four-momentum transfer squared region, from  \(2 \times 10^{-4}\) to \(10^{-2} (GeV/C^2)\), with sub-percent precision.

The PRad experiment utilizes a pair of large area, high spatial resolution GEM detectors, and a non-magnetic calorimeter (HyCal). PRad experiment has superior ways to control systematic errors, the e-p elastic scattering cross-section will be normalized to the well known moller scattering process, which is simultaneously measured with similar kinematics and the same appratus, this greatly reduces the uncertainties from luminosity, detector efficiency and acceptance, etc; and PRad covers a large \(Q^2\) range in one experimental setting. With the data in low \(Q^2\) region, we hope to reach sub-percent precision and model independent extraction of proton charge radius.

In this talk we will present the detailed experimental method and setup, and the current data analysis status.

Condensed Matter


Tuesday, April 11, 2017
3:30 PM
Physics Building, Room 204

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ABSTRACT:

The unique Fe vacancy ordering in alkali metal doped iron selenide \(A_xFe_{2-y}Se_2\) (A=K, Rb, Cs, \(\cdots\)) has drawn a lot of attention among the Fe-based superconductor community. In this work we investigated the effects of annealing on Fe vacancy in \(K_xFe_{2-y}Se_2\) single crystal samples by high energy X-ray diffraction and Monte Carlo simulation. The X-ray results indicated that the I4/mmm phase volume fraction decreased after annealing, while the simulation results demonstrated that this shrink of I4/mmm phase is accompanied with a expand of the Fe vacancy disordered area at the domain boundaries. Together with the well known annealing induced superconductivity enhancement, we found that superconductivity in this system is most likely related to the Fe vacancy disordered region.

Nuclear
Tuesday, April 4, 2017
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, March 28, 2017
3:30 PM
Physics Building, Room 204

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"Recent Results on Hadron Tomography using the Generalized Parton Distributions"


Raphael Dupre , Institut de Physique Nucléaire d'Orsay
[Host: Simonetta Liuti]
Nuclear
Tuesday, March 21, 2017
3:30 PM
Physics Building, Room 204

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"Dark Astronomical Compact Object (DACO) and its implications"


Dat Duong , UVA-Physics
[Host: Bob Hirosky]
ABSTRACT:

Strongly self-interacting dark matter (SSIDM) was proposed as a candidate which might be able to solve astrophysical problems plaguing collisionless cold dark matter: the cusp-vs-core, the missing satellite and the too-big-to-fail problems. These SSIDM particles can in principle form bound states. In particular, if the SSIDM particles belong to a confining gauge group, the singlet states (similar to the baryons of QCD but whose spin depends on the gauge group), the so-called dark "baryons", can cluster into astronomical compact objects which will be called Dark Astronomical Extreme Compact Objects (DAECO) in this paper. How massive can they be? What are their typical sizes? Depending on the mass of the dark baryon, a DAECO can be as "large" as 33 Earth mass for a 1-TeV dark baryon to 0.3 Earth mass for a 10-TeV dark baryon. These DAECOs are extremely small: 15 cm for the 33-Earth mass DAECO and 1.5 mm for the 0.3-Earth mass one. These planetary-mass-type DAECO’S could be "detected" for using techniques such as the astrometric measurements as applied to the searches for exoplanets. Specifically, one would look for gravitational influences of DAECOS’s on a given star when they come close to it. The search for DAECO’s, if they exist, would provide a "direct" detection of strongly self-interacting dark matter at an astronomical level, somewhat similar to laboratory direct detection searches through the detection of nuclear recoil. Another possibility is the merger of two clusters of DAECOs with each having a mass ∼ 30 M generating gravitational waves of the types observed by LIGO.

SLIDESHOW:
Nuclear
Tuesday, March 14, 2017
3:30 PM
Physics Building, Room 204

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"GEM detectors for new generation nucleon form factor experiments in Hall A at JLab"


Danning Di , UVA- Department of Physics
[Host: Nilanga Liyanage]
ABSTRACT:

The electromagnetic form factors of the nucleon are essential for our understanding of the structure of the nucleon. Precision measurements of nucleon form factors is a fundamental part the Je erson Lab experimental program. The 12 GeV beam upgrade and the newly designed Super BigBite Spectrometer make possible a new generation of experiments to measure nucleon form factors with high precision at high Q2 values around 10 GeV2. The concept of the Super BigBite Spectrometer, which provides large solid angle and the capability to operate at  high luminosity, is based on new Gas Electron Multiplier (GEM) detector based particle trackers. The SBS GEM chambers are expected to provides a good position resolution of 70 m, while operating in high rate conditions up to 0.5 MHz=mm2. A set of 40 GEM detectors, each with an active area of 60x50 cm2, has been built in the GEM detector lab at UVa for the the proton polarimeter trackers of SBS. This seminar will present an overview of SBS nucleon form factor experiments and will report on the Research, development and testing of SBS GEM chamber data acquisition system which is essential to make those high rate experiments possible.
 

Nuclear
Tuesday, February 28, 2017
3:30 PM
Physics Building, Room 204

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Reserved - Please see the Colloquia schedule
Nuclear
Tuesday, February 21, 2017
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, February 14, 2017
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, February 7, 2017
3:30 PM
Physics Building, Room 204

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Reserved - Please see the Colloquia Schedule
Nuclear
Tuesday, January 31, 2017
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, January 24, 2017
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, December 6, 2016
3:30 PM
Physics Building, Room 204

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"Measurement of the Fierz term in neutron beta decay"


Kevin Hickerson , Caltech
[Host: Stefan Baessler]
Nuclear
Tuesday, November 29, 2016
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, November 22, 2016
3:30 PM
Physics Building, Room 204

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Special Nuclear/High Energy Seminar


Thursday, November 17, 2016
3:30 PM
Physics Building, Room 204

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"Heavy-Ion Collisions at the LHC: from QCD to QGP"


Pasquale Di Nezza , Instituto Nazionale di Fisica - LNF (Rome) and CERN
[Host: Simonetta Liuti]
Nuclear
Tuesday, November 15, 2016
11:00 AM
Physics Building, Room 313

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"E1039 at FNAL: A polarized proton target to measure the Sivers asymmetry of light sea quarks"


David Kleinjan , Los Alamos National Laboratory
[Host: D. G. Crabb]
Nuclear
Tuesday, November 15, 2016
3:30 PM
Physics Building, Room 204

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"Astromaterial Science"


Matt Caplan , Indiana University
[Host: Donal Day]
ABSTRACT:

Stars freeze. But not all of them. Only some parts of some stars will. In white dwarfs and neutron stars, despite temperatures of millions of degrees, the densities and pressures are great enough to compact nuclei into a crystalline lattice millions of times more dense than any material on earth. Deeper still in neutron stars, near the nuclear saturation density, nuclei begin to touch and rearrange into non-spherical structures called 'nuclear pasta.' To interpret observations of neutron stars the composition and structure of the crystal and pasta layers must be understood, as the microscopic properties of the crust determine the macroscopic properties of the star, such as its thermal and electrical conductivity. At Indiana University, we perform computer simulations of these exotic astromaterials to calculate the physical properties of these stars.

SLIDESHOW:
Nuclear
Monday, November 14, 2016
3:30 PM
Physics Building, Room 313

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Nuclear
Tuesday, November 8, 2016
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, November 1, 2016
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, October 25, 2016
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, October 18, 2016
3:30 PM
Physics Building, Room 204

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RESERVED
Nuclear
Tuesday, October 11, 2016
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, October 4, 2016
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, September 27, 2016
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, September 20, 2016
3:30 PM
Physics Building, Room 204

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RESERVED
Nuclear
Tuesday, September 13, 2016
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, September 6, 2016
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, August 30, 2016
3:30 PM
Physics Building, Room 204

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"Reserved"


Reserved
Nuclear
Tuesday, August 23, 2016
3:30 PM
Physics Building, Room 204

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RESERVED
Nuclear
Tuesday, May 3, 2016
3:30 PM
Physics Building, Room 204

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ABSTRACT:

The ratio of decay rates \(\Gamma(\pi{\to}ev^{-}(\gamma))/\Gamma(\pi{\to}{\mu}v^-(\gamma))\) provides a key confirmation of the V−A nature of the electroweak interaction. Currently, the experimenally determined value of this ratio is\(R^{exp}_{e/\mu} = (1.230\pm0.004)\times10^{-4}\), whereas the theoretically determined value according to Standard Model physics is \(R^{SM}_{e/\mu} = (1.2356\pm0.0001)\times10^{-4}\). This \(\pi_{2e}\) branching ratio proves one of the most sensitive tests for lepton universality. The branching ratio can also be used to give mass bounds on “new” , or non V−A, particles e/µ and interactions. It is for this reason the PEN group, an international collaboration led by University of Virginia, has undertaken to measure \(R^{exp}_{e/\mu}\) to a precision of 5 × \(10^{-4}\) or better. I will discuss the challenges and analysis techniques to extract \(\pi_{2e}\) branching ratio with more emphasis on the Monte Carlo simulation that aids in determining necessary quantities for branching ratio extraction.

 

SLIDESHOW:
Nuclear
Tuesday, April 26, 2016
3:30 PM
Physics Building, Room 204

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RESERVED
Nuclear
Tuesday, April 19, 2016
3:30 PM
Physics Building, Room 204

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"Precise measurement of the electron-neutrino correlation in neutron beta decay"


Wenjiang Fan , UVA- Department of Physics
[Host: Dinko Počanić]
ABSTRACT:

The Nab collaboration at the Spallation Neutron Source (SNS) aims to measure the electron-neutrino correlation parameter "a" with a relative uncertainty of about 10^{-3}, and the Fierz interference term "b" with absolute uncertainty of 3 x 10^{-3}. Nab will use a novel "time of flight" (TOF) EM field spectrometer and segmented Si detectors. The scientific motivation is to provide an independent measurement of the ratio of axial-vector to vector coupling constants of the nucleon to an uncertainty of 0.03% and to test the unitarity of the CKM quark mixing matrix. In the Nab experiment, "a" is determined by combined precise determinations of the electron energy and the proton time of flight. In this talk, we present the motivation of the Nab experiment, the principle and the uncertainty analysis of the measurement of “a”.

SLIDESHOW:
Nuclear
Tuesday, April 12, 2016
3:30 PM
Physics Building, Room 204

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ABSTRACT:

The Nab experiment is designed to a) determine the ratio of axial-vector coupling to vector coupling to an uncertainty of 0.03% error, b) test the unitarity of CKM Matrix and c) measure the Fierz interference term b by studying free neutron beta decay. In neutron beta decay, the electron energy spectrum is modified by the Fierz interference term. Therefore, a precise measure of  the electron energy spectrum could lead to an excellent determination of b. The Nab experiment is expected to measure the Fierz interference term with an uncertainty of about 10^-3. We present the uncertainty analysis of the electron energy spectrum, and show the required limit of the experiment uncertainty in different aspects.

 

Nuclear
Tuesday, April 5, 2016
3:30 PM
Physics Building, Room 204

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ABSTRACT:

Coulomb Sum Rule states that the integration of longitudinal response of a nucleus over the range of energy excitation dominated by quasi-elastic proton knock-out process should be equal to the total number of protons in the nucleus.

The test of Coulomb Sum Rule will shed light on the question of whether or not the properties of nucleon are modified in the nuclear medium.

In order to test the Coulomb Sum Rule in nuclei, a precision measurement of inclusive electron scattering cross sections in the quasi-elastic region was performed at Jefferson Lab.

Incident electrons with energies ranging from 0.4 GeV to 4 GeV scattered from 4He, 12C, 56Fe and 208Pb nuclei at 4 scattering angles(15,60,90,120 degree) and momentum transfer ranging from 0.55 GeV/c to 1 GeV/c.

After complete all the data analysis, we expect to confirm/refute the presently controversial issue of the quenching of the longitudinal response function in medium weight nuclei and as importantly investigate the |q| evolution of the Coulomb Sum Rule as we probe significantly shorter distances.

Nuclear
Tuesday, March 29, 2016
3:30 PM
Physics Building, Room 204

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ABSTRACT:

Time reversal symmetric topological superconductors in three spatial dimensions carry gapless surface Majorana fermions. They are robust against any time reversal symmetric single-body per- turbation weaker than the bulk energy gap. We mimic the massless surface Majorana’s by coupled wire models in two spatial dimensions. We introduce explicit many-body interwire interactions that preserve time reversal symmetry and give energy gaps to all low energy degrees of freedom. We show the gapped models generically carry non-trivial topological order and support anyonic excitations. 

Nuclear
Tuesday, March 22, 2016
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, March 15, 2016
3:30 PM
Physics Building, Room 204

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Available
Nuclear
Tuesday, March 8, 2016
3:30 PM
Physics Building, Room 204

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ABSTRACT:

Analysis of the Drell-Yan process in high energy polarized proton-proton collisions is a unique method for probing the proton spin structure. Measurement of the longitudinal double spin asymmetry ($A_{LL}$) in the Drell-Yan process provides clean access to the anti-quark helicity distributions without involving quark fragmentation functions. In the PHENIX experiment at RHIC, the Forward Silicon Vertex Detector (FVTX), together with forward muon spectrometers, allows us to study the Drell-Yan process by detecting the muon pairs in the forward region (1.2 $< \eta <$ 2.4) while also suppressing backgrounds due to heavy-flavor production. In this talk, the Drell-Yan $A_{LL}$ measurement for the intermediate mass region (4.0 GeV $< M <$ 8 GeV) using the RHIC 2013 data of proton-proton collisions at a center of mass energy of 510 GeV is presented.

Nuclear
Tuesday, February 23, 2016
3:30 PM
Physics Building, Room 204

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RESERVED
Nuclear
Friday, February 19, 2016
11:00 AM
Physics Building, Room 313

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"Does the Gluon Carry Proton's Spin"


Hari Guragain , Georgia State University
[Host: Donal Day]
ABSTRACT:

I will present the PHENIX measurements for the cross section and double-helicity asymmetry (ALL) in inclusive π0 production at midrapidity from p + p collisions at √s = 510 GeV from data taken in 2012 and 2013 at the Relativistic Heavy Ion Collider. The next-to-leading-order perturbative-quantum chromodynamics theory calculation is in excellent agreement with the presented cross section results. The calculation utilized parton-to-pion fragmentation functions from the recent DSS14 global analysis, which prefer a smaller gluon-to-pion fragmentation function. The π0 ALL results follow an increasingly positive asymmetry trend with pT and √s with respect to the predictions and are in excellent agreement with the latest global analysis results. This analysis incorporated earlier results on π0 and jet ALL and suggested a positive contribution of gluon polarization to the spin of the proton ΔG for the gluon momentum fraction range x > 0.05. The data presented here extend to a currently unexplored region, down to x ∼ 0.01, and thus provide additional constraints on the value of ΔG.

SLIDESHOW:
Nuclear
Tuesday, February 16, 2016
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, February 9, 2016
3:30 PM
Physics Building, Room 204

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Available
Nuclear
Tuesday, February 2, 2016
3:30 PM
Physics Building, Room 204

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"Why the Proton Radius is Smaller In Virginia"


Doug Higinbotham , JLAB
[Host: Blaine Norum]
ABSTRACT:

Recent Muonic hydrogen measurements have determined the proton's charge radius to be 0.84fm, a result systematically different from both the atomic hydrogen results and electron scattering results of ~0.88fm.  In an effort to under this "puzzle",  I will present, from a historical perspective, how the proton's charge radius has been  extracted from electron scattering data starting with the 1963 review article by Hand et al., with its 0.81(1)fm standard dipole radius and working my way to up the ~0.88(1)fm 2014 results from Mainz.   I will then discuss why groups in Virginia (JLab, UVA, and W&M) are extracting a radius very close to the Muonic result as well as discuss some of the pitfalls of multivariate fitting.

SLIDESHOW:
Nuclear
Tuesday, January 26, 2016
3:30 PM
Physics Building, Room 204

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ABSTRACT:

I will review the new cross section and charge radius results from the Jefferson Lab’s “LEDEX” experiment. This experiment includes measurements on several light nuclei, hydrogen, deuteron, lithium, boron, and carbon with beam energies down to 360 MeV and spectrometer angles down to 12.5 degrees. To test our ability to measure absolute cross sections, as well as our ability to extract the charge radius, we first testd our technique against the extremely well measured 12C case and found excellent agreement using the Fourier-Bessel parameterization. Our new results on boron (2.40 ± 0.12 fm) and lithium (2.52±0.05 fm) are in nice agreement with model independent variational monte carlo calculations. For the lightest nuclei, we clearly see the limits of this technique and will show why for those nuclei the radius is not determined from a Fourier-Bessel technique but by determinining the slope at q2 = 0.

SLIDESHOW:
Nuclear
Tuesday, December 8, 2015
3:30 PM
Physics Building, Room 204

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Reserved for Chemistry
ABSTRACT:

Reserved for Chemistry

Nuclear
Thursday, December 3, 2015
2:00 PM
Physics Building, Room 205

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SLIDESHOW:
Nuclear
Tuesday, December 1, 2015
3:30 PM
Physics Building, Room 204

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RESERVED
Nuclear
Tuesday, November 24, 2015
3:30 PM
Physics Building, Room 204

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Available
Nuclear
Tuesday, November 17, 2015
3:30 PM
Physics Building, Room 204

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"Search for Time Reversal Violation in Polarized Neutron Optics"


William M. Snow , Indiana University /IUCF
[Host: D. G. Crabb]
ABSTRACT:

Sensitive searches for time reversal violation in many different systems are very important scientifically to probe physics beyond the Standard Model and to search for processes which could help explain the matter-antimatter asymmetry of the universe.

We discuss the possibility of exploiting the already-observed large amplifications of neutron-nucleus parity violation  to search for T-odd effects in polarized neutron transmission through polarized targets.

SLIDESHOW:
Nuclear
Tuesday, November 10, 2015
3:30 PM
Physics Building, Room 204

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"Parity Violating Electron Scattering Experiments"


Dr. Rakitha Beminiwattha , Syracuse University
[Host: Nilanga Liyanage]
ABSTRACT:

Parity Violating Electron Scattering (PVES) is an extremely successful precision frontier tool that have been using for testing the Standard Model (SM) and understanding nucleon structure. Historically, 1978 pioneering Prescott experiment at SLAC was the first successful PVES experiment that confirmed the electroweak theory of particle physics developed by S. Glashow, S. Weinberg and A. Salam as the SM of the particle physics. Several generations of highly successful PVES programs (SAMPLE, A4, HAPPEX, G0 and SLAC E158 programs) have contributed to understanding of nucleon structure and testing the SM.

But missing phenomena like matter antimatter asymmetry, neutrino flavor oscillations, and dark matter and energy suggest that the SM is only a “low energy” effective theory.

Precision PVES measurements of SM predicted quantities can be used to constrain or discover new physics models beyond the SM. In nuclear physics the “EMC effect” has not yet been properly explained. Therefore an important question in hadronic physics is how protons and neutrons are modified when they are bound in a nucleus. A precise measurement of the neutron skin thickness which is a fundamental test of nuclear theory, will pin down the density dependence of the symmetry energy of neutron rich nuclear matter which has impacts on heavy ion collisions and neutron stars. The current and next generation PVES experiments will provide answers to these questions. Qweak and SoLID­PVDIS will provide a precision test of the Standard Model through an unique constraints on neutral electron­quark effective couplings while MOLLER will provide same through neutral electron­electron coupling. The Lead Radius Experiment PREX will provide a clean measurement of the neutron skin thickness. I will introduce PVES experimental techniques and discuss current generation PVES Qweak and PREX experiments and next generation PVES SoLID­PVDIS and MOLLER experiments.

REX experiments and next generation PVES SoLID­PVDIS and MOLLER experiments.

The “EMC effect,” was some of the first data observed that there is a significant change on the quark level and that the identities of the nucleons are different. It showed a depletion of quarks in the valence region and despite sophisticated modeling, cannot be described by simple binding effects. Despite decades of theoretical efforts, a rigorous explanation has been elusive.

A precise measurement of neutron skin thickness which is a fundamental test of nuclear theory, will pins down the density dependence of the symmetry energy of neutron rich nuclear matter which has impacts on heavy ion collisions and neutron star structure.and understanding the nuclear medium effects on structure of quarks. PVES program at Jefferson Lab

For Qweak

After a decade of preparations, the \Qweak experiment at Jefferson Lab is making the first direct measurement of the weak charge of the proton, $\mathrm{Q^p_W}$. This quantity is

suppressed in the \acl{acro­sm} making a good candidate for search for new physics beyond the \acs{acro­sm} at the TeV scale. Operationally, we measure a small (about $\rm ­0.200\ ppm

$) parity­violating asymmetry in elastic electron­proton scattering in integrating mode while flipping the helicity of the electrons 1000 times per second.

Commissioning took place Fall 2010, and we finished taking data in early summer 2012. This dissertation is based on the data taken on an initial two weeks period (Wien0). It will provide an overview of the \Qweak apparatus, description of the data acquisition and analysis software systems, and final analysis and results from the Wien0 data set. The result is a

$\mathrm{16\%}$ measurement of the parity violating electron­proton ($\vec{\rm e}\rm p$) scattering asymmetry, $\rm A = ­0.2788 \pm 0.0348 (stat.) \pm 0.0290 (syst.)\ ppm$ at $\rm Q^2

= 0.0250 \pm 0.0006\ (GeV)^2$. From this a $\rm 21\% $ measurement of the weak charge of the proton, $\rm Q_w^p(msr)=\ +0.0952 \pm 0.0155 (stat.) \pm 0.0131 (syst.) \pm 0.0015 (theory) $ is extracted. From this a $\rm 2\% $ measurement of the weak mixing angle, $\rm sin^2\hat{\theta}_W(msr)= +0.2328 \pm 0.0039 (stat.) \pm 0.0033 (syst.) \pm 0.0004 (theory)$ and improved constraints on isoscalar/isovector effective coupling constants of the weak neutral hadronic currents are extracted. These results deviate from the \acl{acro­sm} by one standard deviation. The Wien0 results are a proof of principle of the \Qweak data analysis and a highlight of the road ahead for obtaining full results.

For SoLID

A new proposal to measure parity violating deep inelastic asymmetry (PVDIS) will provide a precision test of the Standard Model through an unique constraints on axial­vector neutral electron­quark effective couplings and a precision measurement of the weak mixing angle. We plan to measure the asymmetry to about $\rm 0.5 \% $ precision over the Bjoken x from 0.3 to

0.7 where the PV asymmetry is approximately independent of hadronic structure. If any deviations observed, the residual hadronic and new physics contributions in the asymmetry could be separated by kinematic dependence of the PVDIS asymmetry. At the proposed precision level, asymmetry will be sensitive to novel hadronic structure effects including charge symmetry violation (CSV) effects and higher twist effects. Observation of these effects itself will be beneficial to building better theoretical models. A deuterium target will be used for Standard Model tests while a d/u quark distribution ratio measurement is proposed using a hydrogen target.

The broad reach in kinematic and high statistical precision at which PVDIS asymmetries are planned to measure, a large angle acceptance, high luminosity, and large azimuthal acceptance device is a necessity. We are proposing a new spectrometer based on a solenoid magnet called Solenoidal Large Intensity Device (SoLID) that will provide broad range of electroweak and QCD physics measurements to be conducted at the Jefferson Laboratory. The apparatus will have set of tracking gas electron multiplier (GEM) detectors, a gas Cerenkov detector, and a sampling electromagnetic calorimeter to provide particle identification. The experiment will be conducted as a high rate counting mode experiment.

SLIDESHOW:
Nuclear
Tuesday, November 3, 2015
3:30 PM
Physics Building, Room 204

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RESERVED
Nuclear
Tuesday, October 27, 2015
3:30 PM
Physics Building, Room 204

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Reserved for Chemistry
ABSTRACT:

Chemistry Department Seminar from 3:30 - 5:30pm

Nuclear
Tuesday, October 20, 2015
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, October 13, 2015
3:30 PM
Physics Building, Room 204

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Available
Nuclear
Tuesday, October 6, 2015
3:30 PM
Physics Building, Room 204

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"Towards a unified description of the electroweak nuclear response"


Omar Benhar , University of Rome (La Sapienza)
[Host: Donal Day]
ABSTRACT:

Over the past two decades, the availability of a large body of electron-nucleus scattering data of unprecedented accuracy has triggered the development of highly refined theoretical approaches, based on realistic descriptions of both nuclear structure and the nuclear electromagnetic current, which have proved remarkably successful in explaining the experimental results. The extension of these approaches to the study of neutrino-nucleus interactions is needed to clarify a number of outstanding issues in both neutrino physics and astrophysics. I will discuss the results of recent work, aimed at developing a unified description of neutrino-nucleus interactions in the energy range extending from the few MeV region, relevant to astrophysical applications, to the few GeV region, relevant to long-baseline neutrino oscillation experiments.

SLIDESHOW:
Nuclear
Tuesday, September 29, 2015
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, September 22, 2015
3:30 PM
Physics Building, Room 204

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Available
Nuclear
Tuesday, September 15, 2015
3:30 PM
Physics Building, Room 204

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Available
Nuclear
Tuesday, September 8, 2015
3:30 PM
Physics Building, Room 204

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RESERVED
Nuclear
Tuesday, September 1, 2015
3:30 PM
Physics Building, Room 204

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Available
Nuclear
Tuesday, August 25, 2015
3:30 PM
Physics Building, Room 204

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Available
Nuclear
Thursday, August 13, 2015
3:30 PM
Physics Building, Room 313

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"A Cryogenic Target for Compton Scattering Experiments a HIGS"


David Kendellen , Duke University
[Host: Donal Day]
Nuclear
Thursday, May 14, 2015
2:00 PM
Physics Building, Room 204

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"Status and Analysis of the NPDGamma Experiment"


Jason Fry , University of Indiana
[Host: Dinko Pocanic]
ABSTRACT:

The NPDGamma Experiment measured the parity violating gamma asymmetry from polarized neutrons captured on protons at the Spallation Neutron Source at ORNL. This parity violating asymmetry is proportional to the isovector contribution of the hadronic weak interaction (HWI) and has been measured to a precision of 13ppb which can help resolve the unconstrained coupling space of the HWI. As one of the parallel analyses of NPDGamma, we present a statistically optimal algorithm using a least squares fit to the 60Hz neutron pulses in order to filter, and make high level cuts on, production data.

SLIDESHOW:
Nuclear
Tuesday, April 28, 2015
3:30 PM
Physics Building, Room 204

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Available
Nuclear
Tuesday, April 21, 2015
3:30 PM
Physics Building, Room 204

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Reserved for HEP Seminar
Nuclear
Tuesday, April 7, 2015
3:30 PM
Physics Building, Room 204

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Reserved for Condensed Matter Seminar
Nuclear
Tuesday, March 31, 2015
3:30 PM
Physics Building, Room 204

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"Techniques of Uncertainty Reduction and Signal Extraction in Nuclear Physics"


Dustin Keller , University of Virginia
[Host: Don Crabb]
ABSTRACT:

Frequently small signals of interest are overwhelmed by background, systematic uncertainty, or statistical limitations. These types of constraints can degrade the quality of the observables under investigation. In some cases it is possible to improve the figure of merit using analytical tools while in others an experiment must be tactfully designed with error mitigation in mind. For a demonstration in error minimization in data analysis some branching ratios of the electromagnetic decays of the lower mass strange baryons are extracted using data from the CEBAF Large Acceptance Spectrometer (CLAS) detector in Hall B at Thomas Jefferson National Accelerator Facility. Some further examples are used for other experimental Halls as well as applications to systematic error minimization and plausible beam time reduction for polarized target experiments.

Nuclear
Tuesday, March 24, 2015
3:30 PM
Physics Building, Room 204

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"A measurement of two-photon exchange in unpolarized elastic electron-proton scattering"


Mikhail Yurov , University of Virginia
[Host: Donal Day]
ABSTRACT:

Jefferson Lab experiment E05-017 was designed to study 2-photon exchange contributions to elastic electron-proton scattering over a wide kinematic range. By detecting the scattered proton instead of the electron these measurements will be very sensitive to the epsilon dependence of the cross section and consequently the ratio of the electromagnetic form factors. The goals of the experiment, the experimental technique and the kinematic range will be presented. The analysis sequence and results of the early steps will be outlined.

SLIDESHOW:
Nuclear
Tuesday, March 17, 2015
3:30 PM
Physics Building, Room 204

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"Upcoming Measurements of the Neutron Lifetime to 1 Second and Why You Should Care"


Jonathan Mulholland , University of Tennessee - Knoxville & NIST
[Host: Donal Day]
ABSTRACT:

The decay of the free neutron is the archetypal charged current semi-leptonic weak process. As such, experimental investigation of the decay process through lifetime and decay correlation measurements provide insight into a wide variety of physics, ranging from fundamental interactions to the formation of the early Universe. I will discuss some of the history of neutron decay measurements, the neutron lifetime's role in big bang nucleosynthesis, and my work on the upcoming in-beam measurement of the neutron lifetime at the NIST Center for Neutron Research.

SLIDESHOW:
Nuclear
Tuesday, March 3, 2015
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, February 24, 2015
3:30 PM
Physics Building, Room 204

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ABSTRACT:

Short Range Correlations (SRCs) have been recognized as responsible for the high momentum tail of the nucleon momentum distribution. Several experiments at Jefferson Lab have exploited inclusive scattering to study about SRCs by going to X_bj >2. In an upcoming tritium experiment (E12-11-112) we will perform a precision test of isospin dependence of two-nucleon short-range correlations using mirror nuclei: 3He and 3H. The data taken at x>2 will also be used to study three-nucleon short-range correlations. In this talk we will briefly present the motivation for this experiment as well as some of the experimental details and the expected results. In addition, we will discuss a method to check the absolute target thickness of sealed tritium cell through elastic scattering measurement.

SLIDESHOW:
Nuclear
Tuesday, February 10, 2015
3:30 PM
Physics Building, Room 204

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RESERVED
Nuclear
Tuesday, February 3, 2015
3:30 PM
Physics Building, Room 204

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Available
Nuclear
Tuesday, January 27, 2015
3:30 PM
Physics Building, Room 204

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RESERVED
Nuclear
Tuesday, January 20, 2015
3:30 PM
Physics Building, Room 204

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"Parity Violation in Hadronic Systems"


Christopher Crawford , University of Kentucky
[Host: Stefan Baessler]
ABSTRACT:

Parity violation (PV) was first observed in semileptonic beta decays, and has been mapped out precisely at the quark and lepton level as part of the standard model. However, PV in hadronic systems has proven much more elusive, where the strong interaction dominates by seven orders of magnitude. These weak contributions have been classified in chiral effective field theory in terms of the spin and isospin dependence of transition amplitudes involving S and P waves. There is an active program to determine the EFT parameters by measuring hadronic PV using cold neutron beams at the Spallation Neutron Source (ORNL) and the NCNR reactor (NIST). These experiments use only few-body observables, for which nuclear wave functions are calculable. The NPDGamma experiment recently completed taking data of the PV gamma spin asymmetry in the reaction n + p -> d + gamma. We have commissioned the follow-up experiment n3He to measure the proton spin asymmetry in the reaction n + 3He -> 3H + p. These two experiments, along with elastic PV proton-proton scattering, will help isolate the four dominant contributions to the PV hadronic weak interaction.

SLIDESHOW:
Nuclear
Tuesday, January 13, 2015
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, December 2, 2014
3:30 PM
Physics Building, Room 204

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Available
Nuclear
Tuesday, November 25, 2014
3:30 PM
Physics Building, Room 204

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Available
GPSA talk (Primarily meant for students)


Monday, November 24, 2014
3:30 PM
Physics Building, Room 204

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"What makes the proton spin?"


Abha Rajan , University of Virginia
[Host: GPSA]
ABSTRACT:

The spin of the proton is a source of great mystery: how do the spins and other angular momentum of gluons and quarks add up to the spin of the proton? The so called 'spin puzzle' came up because the measurement of the valence quarks spin (EMC experiment at CERN, 1987) was found to be way smaller than the expected 0.5 (spin of the proton). My research focusses on the theory describing the component of angular momentum generated by motion of quarks and gluons (partons). This includes working with different types of distribution functions such as the regular Parton Distribution Functions, Generalised Parton Distribution Functions and Transverse Momentum Distributions. In my talk, I will highlight how we describe partonic angular momentum using these distributions and how we approach the problem of measuring it experimentally.

Nuclear
Tuesday, November 18, 2014
3:30 PM
Physics Building, Room 204

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Unavailable
Nuclear
Tuesday, November 11, 2014
3:30 PM
Physics Building, Room 204

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RESERVED
Nuclear
Tuesday, November 4, 2014
3:30 PM
Physics Building, Room 204

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Unavailable
Nuclear
Tuesday, October 28, 2014
3:30 PM
Physics Building, Room 204

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Available
GPSA talk (Primarily meant for students)


Tuesday, October 21, 2014
3:30 PM
Physics Building, Room 204

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"Phase transitions beyond the Landau-Ginzburg theory"


Yifei Shi , University of Virginia
[Host: GPSA]
ABSTRACT:

Critical behavior and phase transitions are of great interest in condensed matter physics. In this talk we introduce the basic concepts about criticality, as well as theoretical and numerical tools to study critical phenomena. The Landau-Ginzburg theory, or the "Order parameter" picture has been successful in describing many systems with second order phase transitions, for example in superconductors. But here we'll also see a 2D modified XY model that has phase transitions that doesn't not fit into the traditional description.

 

* Refreshments will be available at the talk.

SLIDESHOW:
Nuclear
Tuesday, October 7, 2014
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, September 30, 2014
3:30 PM
Physics Building, Room 204

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Available
Nuclear
Tuesday, September 23, 2014
3:30 PM
Physics Building, Room 204

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Available
Nuclear
Tuesday, September 16, 2014
3:30 PM
Physics Building, Room 204

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"What can QCD teach us about Dark Matter?"


Alexandre Deur , Jefferson Lab
[Host: Nilanga Liyanage]
ABSTRACT:

QCD has provided the theoretical ground for the two leading classes of dark matter candidates:

WIMPS and axions. However, both have remained elusive to direct detections. In this talk, I will show that QCD can inspire us further on the quest for dark matter. I will discuss the theoretical resemblance between gravity and QCD, as well as phenomenological similarities between dark matter and hadronic physics. These parallels suggest that gravity's self-interaction may play an important role in dark matter phenomenology. I will then discuss experimental supports for this new approach.

SLIDESHOW:
Nuclear
Tuesday, September 9, 2014
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, September 2, 2014
3:30 PM
Physics Building, Room 204

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Available
Nuclear
Tuesday, August 26, 2014
3:30 PM
Physics Building, Room 204

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Available
Nuclear
Tuesday, May 27, 2014
2:00 PM
Physics Building, Room 313

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"Direct neutrino mass measurement with the KATRIN experiment"


Ferenc Glück , KIT Karlsruhe / Germany
[Host: Stefan Baessler]
ABSTRACT:
The aim of the KArlsruhe TRItium Neutrino experiment KATRIN is the direct and model independent determination of the absolute neutrino mass scale down to 0.2 eV. For this purpose, the integral electron energy spectrum will be measured close to the endpoint of molecular tritium beta decay. The electrostatic retardation method with magnetic adiabatic collimation (MAC-E filter) combines high energy resolution with high statistics and small background. The various components of the experiment (gaseous tritium source, pumping-transport system, pre- and main spectrometer, detector and rear system) will be reviewed, together with various systematic effect and background issues. In addition, possibilities for light and keV sterile neutrino determinations will also be discussed.
Nuclear
Tuesday, May 13, 2014
3:30 PM
Physics Building, Room 204

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RESERVED
Nuclear
Thursday, May 1, 2014
3:30 PM
Physics Building, Room 102, Dell 2 Building

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"High Luminosity Polarized 3He Targets for Electron Scattering Experiments"


Maduka Kaluarachchi , University of Virginia
[Host: Gordon Cates]
SLIDESHOW:
Nuclear
Tuesday, April 29, 2014
3:30 PM
Physics Building, Room 204

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Reserved for HEP seminar
Nuclear
Tuesday, April 22, 2014
3:30 PM
Physics Building, Room 204

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Available
Nuclear
Tuesday, April 15, 2014
3:30 PM
Physics Building, Room 204

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"Proton Form Factor Puzzle and the CLAS Two-Photon Exchange Experiment"


Dipak Rimal , Florida International University
[Host: Xiaochao Zheng]
ABSTRACT:
The electromagnetic form factors of the proton are extracted by analyzing unpolarized and polarized electron scattering data assuming the Born approximation. The extracted ratios of electric to magnetic form factors (GE/GM) by the two methods show a significant discrepancy that increases with Q2. One possible explanation for the observed discrepancy is the contribution from two-photon exchange (TPE) eff ects, which are not generally accounted for in the standard treatment of radiative corrections. Theoretical calculations estimating the magnitude of the TPE effect are highly model-dependent and limited experimental evidence for such e ffect exists. The ratio of positron-proton to electron-proton elastic scattering cross sections (R = σ(e+ p)/σ(e- p)) provides a model-independent measurement of the TPE e ffect. One such measurement of R was performed by using a mixed electron-positron beam at Jeff erson Lab Hall B. Both electrons and positrons were elastically scattered from a 30-cm-long liquid hydrogen target. The resulting scattered particles were detected in CLAS. The elastic events were then identified by using elastic scattering kinematics. The measurement covers a range of Q2 < 2 GeV2 and 0:1 < ε < 1. In the kinematics of the experiment, our results are consistent with the hadronic calculation of the TPE e ffect by Blunden, Melnitchouk, and Tjon. The details of the CLAS TPE experiment and the results will be discussed.
SLIDESHOW:
Nuclear
Tuesday, April 8, 2014
3:30 PM
Physics Building, Room 204

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"The g2p experiment and polarized He-3 target upgrade at Jefferson Lab"


Jie Liu , University of Virginia
[Host: Xiaochao Zheng]
SLIDESHOW:
Special Nuclear Seminar
Monday, April 7, 2014
3:30 PM
Physics Building, Room 204

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"Short-Distance Structure of the Nucleus"


Vince Sulkolsky , Longwood University
[Host: Xiaochao Zheng]
ABSTRACT:
One of Jefferson Lab's original missions was to further our understanding of the short-distance structure of nuclei. In particular, to understand what happens when two or more nucleons within a nucleus have strongly overlapping wave-functions; a phenomena commonly referred to as short-range correlations (SRC). I will review recent, Q^2 > 1 [GeV/c]^2 and Bjorken x > 1, (e,e') and (e,e'pN) data that have been used to probe the short-distance structure of the nucleus. New results using a Helium-4 target, which were recently released for publication, will be discussed along with future plans after the energy upgrade of Jefferson Lab.
SLIDESHOW:
Nuclear
Tuesday, April 1, 2014
3:30 PM
Physics Building, Room 204

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"Observability of Quarks and Gluons Orbital Angular Momentum"


Abha Rajan , University of Virginia
[Host: Simonetta Liuti]
SLIDESHOW:
Nuclear
Tuesday, March 25, 2014
3:30 PM
Physics Building, Room 204

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ABSTRACT:
The quantity d2, written as an x2-weighted moment of a linear combination of the spin structure functions g1 and g2, has the interpretation of being the average transverse Lorentz color force felt by a quark immediately following its interaction with a virtual photon in the deep inelastic scattering (DIS) process due to the remnant di-quark system. It has been calculated in diff erent nucleon structure models and in lattice QCD, where it is seen to be small and negative for Q2 > 4 GeV2. The existing measurement for the matrix element d2 on the neutron from the combined data of SLAC E155 and Jeff erson Lab E99-117 at Q2 = 5 GeV2 disagrees with the lattice QCD calculation by almost two standard deviations. This discrepancy served as the motivation for the E06-014 experiment in Hall A of Je fferson Lab. Double-spin asymmetries and unpolarized cross sections were measured in the scattering of a longitudinally polarized electron beam of energies 4.74 and 5.89 GeV from a longitudinally and transversely polarized 3He target, covering the DIS and resonance regions characterized by 0:25 < x < 0:90 and 2 ≤ Q2 ≤ 7 GeV2. This allowed for the extraction of dn2 matrix element in two ⟨Q2⟩ bins of 3.21 and 4.32 GeV2. Additionally, the virtual photon-nucleon asymmetry An1 was extracted, along with the evaluation of the polarized-to-unpolarized quark ratios Δu ⁄ u and Δd ⁄ d. The matrix element a2 is also obtained from our g1 data. We present the results of our measurements, which are compared to the world data and various theoretical models and lattice QCD calculations. Future plans to measure dn2 and An1 with the upgrade of Je fferson Lab will be discussed.
Nuclear
Tuesday, March 4, 2014
3:30 PM
Physics Building, Room 204

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"Deeply-Virtual Compton Scattering in the 6 GeV era of Jefferson Laboratory"


Silvia Pisano , INFN, Laboratori Nazionali di Frascati
[Host: Simonetta Liuti]
Nuclear
Tuesday, February 11, 2014
3:30 PM
Physics Building, Room 204

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"Confronting electron- and neutrino-nucleus scattering Can the axial mass controversy be resolved?"


Omar Benhar , Center for Neutrino Physics, Virginia Tech and INFN and Dept. of Physics, "Sapienza" University
[Host: Donal Day]
ABSTRACT:
It has been suggested that the difficulties in the interpretation of the flux averaged double-differential neutrino-carbon cross section measured by the MiniBooNE collaboration may due to contributions arising from reaction mechanisms other than single-nucleon knockout. The analysis of the large body of inclusive electron scattering data may provide a clue to pin down the role of the relevant mechanisms in a variety of kinematical regimes, thus shedding light on some of the unresolved issues of neutrino-nucleus scattering. As an example, I will argue that it may help to reconcile the different values of the nucleon axial mass reported by the MiniBooNe and NOMAD Collaborations.
SLIDESHOW:
Special Nuclear Seminar
Wednesday, December 18, 2013
1:00 PM
Physics Building, Room 310

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"Notes on GTMDs in the MIT bag model"


Aurore Courtoy , Universite de Liege
[Host: Simonetta Liuti]
Nuclear
Tuesday, December 10, 2013
3:30 PM
Physics Building, Room 218

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ABSTRACT:
The unique advantages of using polarized 3He as neutron spin filters, such as broadband and wide angular acceptance of neutron beams, have made it widely used among neutron scattering communities. Here we report the current status of the polarized 3He development at the Oak Ridge National Laboratory (ORNL). Over the last several years, we have developed a robust polarized 3He program to meet the increasing needs of 3He based neutron spin filters at ORNL’s High Flux Isotope Reactor (HFIR) and Spallation Neutron Source (SNS). At ORNL, spin-exchange optical pumping is used to produce polarized 3He. Two optical pumping stations have been built in the lab to perform ex situ pumping of 3He. In order to solve the complications in data analysis brought by the 3He polarization relaxation in the ex situ pumping, we have constructed in situ pumping systems for several beamlines which has produced very high 3He polarization (76%) and the polarization has been maintained throughout the experiments. In addition, a novel polarized 3He filling station for the Hybrid Spectrometer (HYSPEC) at SNS is under development. We will present the preliminary test results of this system.
SLIDESHOW:
Nuclear
Tuesday, December 3, 2013
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, November 12, 2013
3:30 PM
Physics Building, Room 204

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"The Ongoing Radium EDM Experiment"


Matthew Dietrich , Argonne National Laboratory
[Host: Gordon Cates]
ABSTRACT:
Radium, due to its simple atomic structure, heavy mass, and large nuclear deformation, is an exciting candidate for a CP violation search in the form of an atomic electric dipole moment (EDM). Since CP violation is expected to play an important role in beyond the standard model physics, such a search is a sensitive probe of new physics. An ongoing experiment at Argonne National Lab, which aims to measure the EDM of laser cooled and trapped radium-225 atoms, has made considerable progress in recent years. Here I report the control and preparation of such atoms as well as the first observation of nuclear precession in trapped radium atoms. Together with the application of an electric field, nuclear precession is the signal that will become the first measurement of radium's EDM.
SLIDESHOW:
Nuclear
Tuesday, November 5, 2013
3:30 PM
Physics Building, Room 204

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"Neutrino Interactions with Nucleons and Nuclei"


Ulrich Mosel , University of Giessen
[Host: Donal Day]
ABSTRACT:
Presently ongoing or planned neutrino long baseline experiments all use nuclear targets. Any extraction of neutrino properties from observables in such experiments thus has to deal with the in-medium production and the final state interactions of outgoing particles. Traditionally, this has been done with neutrino event generators. In this talk I will show that the widely used neutrino generators have not yet reached the degree of sophistication of the experimental equipment for neutrino experiments. I will disuss the essential nuclear physics input for neutrino generators: QE, many-body interactions, pion production through resonances and DIS. I will then illustrate how all of these processes affect the event characterization, energy reconstruction and the extraction of neutrino oscillation parameters, using results from the nuclear physics based transport code GiBUU.
SLIDESHOW:
Nuclear
Tuesday, October 22, 2013
3:30 PM
Physics Building, Room 204

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"Measurement of polarization observables in the reaction γp → pπ0π0 in the CBELSA/TAPS experiment"


Vahe Sokhoyan , George Washington University and Institute for Nuclear Physics - Mainz
[Host: Blaine Norum]
ABSTRACT:
To unambiguously identify baryon resonances the measurement of polarization observables is of large importance. With the Crystal Barrel/TAPS experiment, located at the ELSA accelerator facility in Bonn, Germany, polarization observables have been determined using a linearly polarized photon beam impinging on a liquid hydrogen target. In this talk an overview of these measurements will be given and new results on the polarization observables IS and IC will be presented for the reaction γp → pπ0π0. A comparison of the results with predictions of the Bonn-Gatchina-partial wave analysis shows that the data provide new constraints for the extraction of baryon resonances. In addition, invariant mass distributions and Dalitz plots, indicating cascade-decays via different excited states will be discussed.

The work was performed by the CBELSA/TAPS Collaboration at the Helmholtz-Institut fuer Strahlen- und Kernphysik (University of Bonn).

SLIDESHOW:
Nuclear
Tuesday, September 24, 2013
3:30 PM
Physics Building, Room 204

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"Precision Measurements with the Neutron at Low Energies and High Intensities"


Dave Phillips , North Carolina State University
[Host: Don Crabb]
ABSTRACT:
Precision measurements of neutron interactions at low energies and high intensities off er many avenues to search for physics beyond the Standard Model. Motivated by this particle physics impact, there are ongoing experimental programs which utilize cold and ultra-cold neutrons (UCN) to measure the neutron static electric dipole moment, neutron β-decay parameters, and possible new short range interactions. In this talk, we will focus on two such programs: a β-decay program at Los Alamos National Laboratory (LANL) utilizing UCNs and a proposed experiment to search for neutron-antineutron oscillations at Fermi National Accelerator Laboratory (FNAL). Modern studies of neutron β-decay o ffer an improved, nuclear structure independent determination of the CKM matrix element Vud through more precise measurements of the neutron lifetime and β -decay correlation coefficients. Vud is a critical input to a direct test of CKM matrix unitarity, which places stringent limits on extensions to the Standard Model for charged current interactions. This talk will begin with a summary of the UCNA experiment at LANL, the only experiment to perform a measurement of angular correlations in neutron β-decay (spin-electron asymmetry parameter A(E)) using UCN. We then present a recently proposed experiment to search for n − ‾n oscillations using free neutrons at FNAL, which would provide a sensitive window to probe for baryon number violating interactions with Δβ = 2, would provide insight into the origin of matter-antimatter asymmetry in the universe and would change our ideas on the energy scales relevant for quark-lepton uni cation and neutrino mass generation. Methods for an improved search for n − ‾n oscillations using free neutrons and recent detector characterization studies for such a search will be discussed.
SLIDESHOW:
Nuclear
Tuesday, September 17, 2013
3:30 PM
Physics Building, Room 204

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Reserved for HEP seminar
Nuclear
Tuesday, May 7, 2013
4:00 PM
Physics Building, Room 313

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"Searches for a hidden sector photon"


Bogdan Wojtsekhowski , Jefferson Lab
[Host: Nilanga Liyanage]
SLIDESHOW:
Nuclear
Tuesday, April 30, 2013
3:30 PM
Physics Building, Room 204

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"Trying to Solve The 30 year old EMC Effect Puzzle"


Doug Higinbotham , Jefferson Lab
[Host: Blaine Norum]
ABSTRACT:
In 1983 the Europeon Muon Collaboration (EMC) published their deep inelastic scattering ratios that showed that partons in heavy nuclei do not behave the same a partons in light nuclei. Over the decades, much work has been done by both experimentalists and theorists to understand why. In 2009, Jefferson Lab provided a new clue to the cause with their light nuclei EMC effect data. These new data pointed to the EMC effect being a local density effect instead of an average effect. Soon after this observation, a phenomenological link between nuclear short-range correlations and the EMC effect was made. This seminar will review both the EMC effect and short-range correlation results and the link that has been made between these two seemingly unrelated experiments.
Nuclear
Tuesday, April 23, 2013
3:30 PM
Physics Building, Room 204

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"The MUSE experiment: addressing the proton radius puzzle via elastic muon scattering"


Evie Downie , The George Washington University
[Host: Blaine Norum]
ABSTRACT:
The MUSE experiment aims to provide key missing information in the quest to resolve the proton radius puzzle: the difference between the 0.88 fm proton radius measured in atomic hydrogen and ep elastic scattering experiments and the 0.84 fm radius measured in muonic hydrogen. Over the last three years since the puzzle emerged, none of the many attempts to find a solution have reached a universally accepted resolution. Possible solutions include novel beyond standard model physics, novel hadronic physics and issues and/or underestimated uncertainties in the ep scattering data.

Recently there have been high precision electron scattering experiments at Mainz and JLab, and further measurements are planned. A series of excitation spectrum measurements on light nuclei are planned at PSI. The MUSE experiment will open up a new line of experimental investigations by measuring elastic muon scattering on the proton at the PSI piM1 beamline.

MUSE will scatter a mixed muon/pion/electron beam on a liquid hydrogen target with a Q^2 range of approximately 0.002 - 0.08 GeV2. Measurements of both μ+ and μ- at multiple beam momenta will enable checks of systematics, determination of two-photon exchange effects and magnetic contributions, and a radius determination at a similar level of precision to existing ep scattering experiments. Simultaneous electron scattering will allow similar tests and a direct comparison of the two probes, providing an excellent test of lepton universality. The physics background, status, and plans for the experiment will be discussed.

Nuclear
Wednesday, April 10, 2013
3:30 PM
Physics Building, Room 204

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"A Measurement of g2p and the Longitudinal-Transverse Spin Polarizability"


Chao Gu , University of Virginia
[Host: Nilanga Liyanage]
ABSTRACT:
The proton spin-dependent structure function g2p in the resonance region has been measured in a recent experiment at Jefferson Lab in Hall A. A polarized electron beam of energy 1.157-3.349 GeV was incident on a transversely polarized NH3 target. An inclusive measurement at 5.69 deg was performed in order to determine the g2p structure function in the Q2 region of 0.02-0.20 GeV2. No measurement of this quantity has been conducted at such a low-Q2 range before. This experiment will allow us to test the Burkhardt-Cottingham sum rule at low Q2 and extract the generalized longitudinal-transverse spin polarizability δLT. Chiral Perturbation Theory (χPT) is expected to work in this kinematic region and this measurement of δLT will give a benchmark test to χPT calculations. In this talk, I will give describe to the experiment and show the latest progress of the on-going analysis.
Nuclear
Tuesday, April 9, 2013
3:30 PM
Physics Building, Room 204

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"The Upcoming GDH Sum Rule Measurement for the Deuteron"


Ryan Duve , University of Virginia
[Host: Blaine Norum]
ABSTRACT:
This talk will introduce the GDH Sum Rule for the deuteron and the technical hurdles involved in making a doubly polarized measurement via the photodisintegration process d(γ,n)p. Three experimental components, the Duke Free Electron Laser Laboratory, the frozen-spin target HiFrost, and the Blowfish detector array, will be discussed, as well as the motivation for measuring the GDH Sum Rule.
Nuclear
Tuesday, April 2, 2013
3:30 PM
Physics Building, Room 204

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"Scan Time Reduction and X-ray Scatter Rejection in Dual Modality Breast Tomosynthesis"


Tushita Patel , University of Virginia
[Host: Mark Williams]
SLIDESHOW:
Nuclear
Thursday, March 28, 2013
3:30 PM
Physics Building, Room 313

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"Beam-Target Double Spin Asymmetry in d(e, e′p)n"


Michael Mayer , Old Dominion University
[Host: Donal Day]
ABSTRACT:
Using the CLAS detector at Jefferson Lab, double spin asymmetries (A||) for quasi-elastic electron scattering off the deuteron have been measured at several beam energies. The data were collected during the EG1 experiment, which scattered longitudinally polarized electrons with energies from 1.6 to 5.8 GeV off a longitudinally polarized cryogenic ND3 target. The double spin asymmetries were measured as a function of photon virtuality Q2 (0.13−3.17 (GeV/c)2), missing momentum (0.0−0.5 GeV/c), and the angle between the (inferred) “spectator” neutron and the momentum transfer direction (θnq). The results from EG1b are compared with a recent model that includes final state interactions using a complete parameterization of nucleon-nucleon scattering. I will discuss the results for the double spin asymmetry and compare them to this model as well as a simplified model using the plane wave impulse approximation.
Nuclear
Tuesday, March 26, 2013
3:30 PM
Physics Building, Room 204

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SLIDESHOW:
Nuclear
Thursday, March 21, 2013
3:30 PM
Physics Building, Room 204

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"Analysis of αs from the realization of quark-hadron duality"


Aurore Courtoy , Université de Liège
[Host: Simonetta Liuti]
SLIDESHOW:
Nuclear
Tuesday, March 19, 2013
3:30 PM
Physics Building, Room 204

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"The X(3872) and characteristics of hadronic bound states in the charm and beauty sector"


Roxanne Springer , Duke University
[Host: Simonetta Liuti]
Nuclear
Wednesday, March 13, 2013
3:30 PM
Physics Building, Room 313

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ABSTRACT:
Differential cross sections for exclusive π ‾ electro-production from the neutron in the reaction e+d → e′+π ‾+p+pr have been measured over a broad kinematics range in the BoNuS experiment, where pr is the recoil proton. The experiment was performed using a radial time projection chamber (RTPC) and the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab Hall B. The RTPC detector was specially built to detect low energy recoil protons and had a valid momentum acceptance from 67 to 250 MeV/c. The differential cross sections for D(e, e′π ‾p)p have been extracted, with the proton detected either by CLAS or by the RTPC. The structure functions σT + εσL, σLT and σTT were determined and will be presented in comparison with MAID and SAID predictions.
Nuclear
Monday, March 11, 2013
3:30 PM
Physics Building, Room 313

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"Phi meson photoproduction at CLAS"


Heghine Seraydaryan , Jefferson Lab
[Host: Donal Day]
ABSTRACT:
Phi meson photoproduction cross section in its neutral decay mode is measured for the reaction gamma p → p (KSKL). The experiment is performed with a tagged photon beam of energy 1.6 -3.6 GeV incident on a liquid hydrogen target of the CLAS at Thomas Jefferson National Accelerator Facility. The final state is identified via reconstruction of KS in the invariant mass of two oppositely charged pions and by requiring missing particle in the reaction gamma p → p KS X to be KL. Presented results significantly enlarge the existing data on phi meson photoproduction. These data, combined with the data from the charged decay mode, will help to constrain different mechanisms of the phi photoproduction.
Nuclear
Friday, March 8, 2013
11:00 AM
Physics Building, Room 313

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"Measurement of the Induced Polarization of Lambda(1116) in Kaon Electroproduction with CLAS"


Marianna Gabrielyan , Florida International University
[Host: Donal Day]
ABSTRACT:
The CLAS Collaboration is using the p(e, e'K+p)π reaction to perform a measurement of the induced polarization of the electroproduced Λ(1116). The parity-violating weak decay of the Λ into pπ (64%) allows extraction of the recoil polarization of the Λ. The present study uses the CEBAF Large Acceptance Spectrometer (CLAS) to detect the scattered electron, the kaon, and the decay proton. CLAS allows for a large kinematic acceptance in Q2 (0.8 ≤ Q2 ≤ 3.5 GeV2), W (1.6 ≤ W ≤ 3.0 GeV), as well as the kaon scattering angle. In this experiment a 5.499 GeV electron beam was incident upon an unpolarized liquid-hydrogen target. The goal is to map out the kinematic dependencies for this polarization observable to provide new constraints for theoretical models of the electromagnetic production of kaon-hyperon final states. Along with previously published photo- and electroproduction cross sections and polarization observables from CLAS, SAPHIR, and GRAAL, these data are needed in a coupled-channel analysis to identify previously unobserved s-channel resonances.
Nuclear
Tuesday, March 5, 2013
3:30 PM
Physics Building, Room 204

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SLIDESHOW:
Nuclear
Tuesday, February 26, 2013
3:30 PM
Physics Building, Room 204

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"A Search For Dark Forces At The Jefferson Lab Free Electron Laser"


Narbe Kalantarians , Hampton University
[Host: Donal Day]
ABSTRACT:
Recent theories of dark matter predict A’ gauge bosons in the mass range of 0.01-10 GeV that couple to charged fermions with a strength of α’/αΕΜ~ 10-4 of the photon or less. The DarkLight (Detecting A Resonance Kinematically with eLectrons Incident on a Gaseous Hydrogen Target) experiment intends to use the 1 MW 100 MeV electron beam at the Jefferson Lab Free Electron Laser incident on a 1019 H2/cm2 thick target to study the process e- + p -> e- + p +e- + e+. A dark force particle would show up as a narrow resonance in the radiated e+ - e- system. DarkLight would explore the A’ mass region 10-100 MeV with sensitivity to couplings as low as a’/aEM ~10-7 with 1/ab of data.
SLIDESHOW:
Nuclear
Tuesday, February 19, 2013
3:30 PM
Physics Building, Room 204

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"Next generation polarized He-3 targets for electron scattering and related processes"


Yunxiao Wang , University of Virginia
[Host: Gordon Cates]
SLIDESHOW:
Nuclear
Tuesday, February 5, 2013
3:30 PM
Physics Building, Room 204

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"Electrostatic Traps as a High Precision Measurement Tool"


Guy Ron , Racah Institute of Physics, Hebrew University of Jerusalem
[Host: Blaine Norum]
ABSTRACT:
Using principles analogous to those of conventional optics it is possible to construct fully electrostatic ion traps which act as a resonant cavity for ion beams. Such traps exhibit an unexpected phenomenon of self-bunching which allows for long lifetimes of trapped ion bunches.
I will present the principles and design of one such electrostatic trap, originally designed at the Weizmann Institute. I will further discuss the experimental possibilities aff orded by such a trap, with emphasis on mass spectroscopy and possible measurements of β decay correlations of trapped radioactive ions. Such measurements allow the study of possible standard model extensions affecting the structure of the weak interaction.
Nuclear
Monday, January 28, 2013
3:30 PM
Physics Building, Room 204

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"Quantum states of matter and anti-matter in gravitational and centrifugal potentials"


V.V. Nesvizhevsky , Institut Laue-Langevin
[Host: Stefan Baessler]
ABSTRACT:
Two phenomena have been observed recently in experiments with slow neutrons: quantum states of ultracold neutrons (UCN) in the Earth’s gravitational field [1] and quantum states of cold neutrons (CN) in the centrifugal potential in the vicinity of a curved mirror [2]. The first experiment presented the first observation of quantum states of matter in a gravitational field; the second one is also known as the neutron whispering gallery effect. They are related by common experimental methods used, by common mathematical description, but also by their applications in elementary particle physics, in quantum optics, in surface science [3]. It is curious that these experiments present the first direct demonstration of the weak equivalence principle for an object in a quantum state. Much more precise measurements of/with these phenomena are going to be performed in a recently constructed second-generation GRANIT spectrometer [4]. Analogous experiments could be probably performed in future with anti-matter atoms [5-6], with interesting applications in various domains of science.

1. V.V. Nesvizhevsky et al, Nature 415, 297 (2002); S. Baessler et al, J. Phys. G 36, 10 (2009).
2. V.V. Nesvizhevsky et al, Nature Phys. 6, 114 (2010).
3. V.V. Nesvizhevsky, Phys.-Uspekhi 53, 645 (2010).
4. S. Baessler et al, Compt. Rend. Phys. 12, 707 (2011)
5. A.Yu. Voronin et al, Phys. Rev. A 83, 032903 (2011).
6. A.Yu. Voronin et al, Phys. Rev. A 85, 014902 (2012).
SLIDESHOW:
Nuclear
Tuesday, December 18, 2012
3:30 PM
Physics Building, Room 204

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ABSTRACT:
A complete characterization of the spectrum of N and Delta resonances is essential to understand the internal structure of the nucleon. Although the Constituent Quark Models(CQM) gives good predictions for resonances in low-energy region(less than 1.8 GeV). For mass states above 1.8 GeV, many of them have not been found in experiment. This discrepancy between theory and experiment can be attributed to two reasons. One reason is that most identified resonances were discovered in piN scattering; thus, the states that couple weakly to this channel will not be seen. Another reason is that the resonances are both broad and overlapping, which make them hard to identify. The photon production of pseudoscalar mesons studied in the G14 experiment gives us a chance to look at the decay channels in pi-pi-N, eta-N, K-Lamda, etc. Moreover the use of polarized beam, polarized targets, and the detection of the polarized recoil nucleon allow us to measure a large number of polarization observables. These observables will help removing the ambiguities in determining the multipoles in partial wave analysis for the identification of the undiscovered nucleon resonances.
Nuclear
Tuesday, December 4, 2012
3:30 PM
Physics Building, Room 204

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"Self Organizing Maps for Extracting Deep Inelastic Scattering Observables"


Evan Askanazi , University of Virginia
[Host: Simonetta Liuti]
Nuclear
Tuesday, November 27, 2012
3:30 PM
Physics Building, Room 204

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"Overview of Spin Studies at Jefferson Lab"


Yelena Prok , Old Dominion University
[Host: Don Crabb]
SLIDESHOW:
Nuclear/Particle Physics Seminar
Tuesday, November 20, 2012
3:30 PM
Physics Building, Room 204

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"TMD-Factorization with Evolution"


Ted Rogers , Stony Brook University
[Host: Simonetta Liuti]
ABSTRACT:
I will discuss applications of perturbative QCD to the study of inclusive processes that are sensitive to the intrinsic transverse motion of bound state constituents of hadrons. Transverse momentum dependent (TMD) factorization is the theoretical framework that is needed to address these processes in perturbation theory.
Factorization refers to the separation of short-distance (hard) physics, which is calculable in perturbative QCD, from the large-distance non-perturbative effects inside the transverse momentum dependent parton distribution and fragmentation functions.
I will summarize recent theoretical developments in TMD-factorization, and discuss current efforts to apply TMD-factorization phenomenologically to extract information about hadron structure.
Nuclear
Tuesday, May 8, 2012
3:30 PM
Physics Building, Room 204

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RESERVED
Nuclear
Tuesday, May 1, 2012
3:30 PM
Physics Building, Room 204

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Reserved for HEP seminar
Nuclear
Tuesday, April 17, 2012
3:30 PM
Physics Building, Room 204

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"Precision Parity-Violating Measurement of the Neutron Skin of Lead"


Kiadtisak Saenboonruang , UVA
[Host: Nilanga Liyanage]
Nuclear
Tuesday, March 20, 2012
3:30 PM
Physics Building, Room 204

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"The nEDM Project: A new cryogenic measurement of the electric dipole moment of the neutron"


David Haase , North Carolina State University
[Host: D.G. Crabb]
ABSTRACT:
A measurement of a non-zero electric dipole moment of the neutron would have implications on our understanding of the Standard Model and the matter-antimatter asymmetry in the present universe. In 1994 Golub and Lamoreaux (Physics Reports 237, 1—62 (1994)) proposed a new measurement strategy that makes use of several unusual properties of liquid helium. A collaboration of 19 US research groups is now pursuing R&D for an experiment to be installed at the Spallation Neutron Source at ORNL. The talk will outline the features and significance of this measurement, and then focus on the cryogenic challenges of the experiment.
SLIDESHOW:
Nuclear
Tuesday, February 28, 2012
3:30 PM
Physics Building, Room 204

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"Precision Compton Electron Beam Polarimetry for the Qweak Experiment"


Donald Jones , University of Virginia
[Host: Kent Paschke]
Nuclear
Tuesday, December 13, 2011
3:30 PM
Physics Building, Room 313

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"Precise Measurement of the π → e υ Branching Ratio"


Martin Lehman , University of Virginia
[Host: Dinko Pocanic]
Nuclear
Wednesday, December 7, 2011
1:00 PM
Physics Building, Room 204

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"Kinematic Issue of GPDs in DVCS"


Chueng-Ryong Ji , North Carolina State University
[Host: Simonetta Liuti]
ABSTRACT:
Generalized Parton Distributions (GPDs) in Deeply Virtual Compton Scattering (DVCS) have been widely recognized and used as a useful tool to explore the quark and gluon structure of the target hadrons. However, we recently pointed out treacherous kinematic issue in analyzing DVCS in terms of GPDs. In this talk, we present our key findings in the simplest possible level of complete amplitude including the lepton current. Implication in the Jefferson Lab experiment of DVCS will also be discussed.
SLIDESHOW:
Nuclear
Tuesday, December 6, 2011
3:30 PM
Physics Building, Room 204

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RESERVED
Nuclear
Tuesday, November 29, 2011
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, November 22, 2011
3:30 PM
Physics Building, Room 204

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"Exploring Early Times in the QGP Evolution through Direct Virtual Photons"


Tom Hemmick , Stony Brook University
[Host: Nilanga Liyanage]
ABSTRACT:
Among the most exciting discoveries about the Quark-Gluon Plasma State is its extraordinary opacity to color-charged objects (quarks and gluons). This property, while facilitating rapid equilibration of the plasma, hides the state at the earliest times from direct measurement. Colorless probes (direct real and virtual photons) provide access to the earliest time scales, but suffer from huge backgrounds of electromagnetic decays of light mesons. In this seminar, we'll explore how the mass of virtual photons can be used to reduce background from light mesons and provide access to the direct plasma "shine" from the earliest times.
SLIDESHOW:
Nuclear
Tuesday, November 15, 2011
3:30 PM
Physics Building, Room 204

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"Spin Physics at RHIC: Recent results and future prospects"


Yousef Makdisi , Brookhaven National Laboratory
[Host: D. G. Crabb]
Nuclear
Tuesday, November 8, 2011
3:30 PM
Physics Building, Room 204

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"The latest on the proton charge radius"


Haiyan Gao , Duke University
[Host: D. G. Crabb]
SLIDESHOW:
Nuclear
Tuesday, November 1, 2011
3:30 PM
Physics Building, Room 204

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Available
Nuclear
Tuesday, October 25, 2011
3:30 PM
Physics Building, Room 204

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RESERVED
Nuclear
Tuesday, October 18, 2011
3:30 PM
Physics Building, Room 204

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"Polarized Proton-Proton Elastic Scattering at RHIC"


Stephen Bueltmann , Old Dominion University
[Host: D. G. Crabb]
ABSTRACT:
The availability of polarized proton beams at RHIC opened a window to an unexplored kinematic region up to a center of mass energy of 500 GeV for elastic and diffractive proton-proton scattering. Besides the measurement of the total scattering cross section, the polarization of the protons leads to a single spin asymmetry $A_N$, arising from an interference between the electromagnetic proton spin-flip and the hadronic non-flip scattering amplitudes. The measurement is sensitive enough to detect a possible hadronic spin-flip contribution, which cannot be ruled out by the available data. Detailed theoretical model calculations are also available for the double spin asymmetries $A_{NN}$ and $A_{SS}$, assuming varying magnitudes of an Odderon contribution to the scattering amplitude, which we will be able to distinguish at the 5\% level. The Odderon is the hypothetical charge and parity odd partner of the dominant Pomeron. Preliminary data from RHIC run 09 taken with the STAR detector will be shown.
SLIDESHOW:
Nuclear
Tuesday, October 4, 2011
3:30 PM
Physics Building, Room 204

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Available
Nuclear
Tuesday, September 27, 2011
3:30 PM
Physics Building, Room 204

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Available
Nuclear
Tuesday, September 20, 2011
3:30 PM
Physics Building, Room 204

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RESERVED
Nuclear
Tuesday, September 13, 2011
3:30 PM
Physics Building, Room 204

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Available
Nuclear
Tuesday, September 6, 2011
3:30 PM
Physics Building, Room 204

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RESERVED
Nuclear
Tuesday, August 30, 2011
3:30 PM
Physics Building, Room 204

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Available
Nuclear
Tuesday, August 23, 2011
3:30 PM
Physics Building, Room 204

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RESERVED
Special Nuclear Seminar
Thursday, June 9, 2011
11:00 AM
Physics Building, Room 313

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"Selected topics in searching for a neutron edm"


Bob Golub , North Carolina State University
[Host: Stefan Baessler]
ABSTRACT:
A non-zero value of the neutron electric dipole moment (nedm) would represent a violation of T reversal and would be strong evidence for new physics beyond the standard model. After presenting an overview of the project and the experimental methods that are being designed into the search for a neutron edm that is foreseen to be carried out at the Oak Ridge Spallation neutron source (SNS) we discuss a newly discovered systematic error and efforts to deal with it.
Nuclear
Tuesday, May 10, 2011
3:30 PM
Physics Building, Room 204

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"Parity Violating Deep Inelastic Scattering (PVDIS) at JLab 6 GeV"


Diancheng Wang , UVa
[Host: Xiaochao Zheng]
Nuclear
Tuesday, May 3, 2011
3:30 PM
Physics Building, Room 204

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"Results from the GRAAL experiment"


Dr. Annalisa D'Angelo , University of Rome (La Sapienza)
ABSTRACT:
The GRAAL experiment was located at the European Synchrotron Radiation Facility (ESRF) in Grenoble (France). It consisted of a Compton backscattered polarized photon beam, of 1.5 GeV maximum energy, and a large solid angle detector (LAGRANgE), optimized for neutral particle detection. Over more than ten years of activity has provided photon beam asymmetry measurements of pseudo-scalar meson photo-production reactions on both proton and neutron targets, providing strong constraints to models that allow for the extraction of nucleon resonances properties from experimental results. Highlights from published data are summarized and the latest results on omega meson photo-production are presented
Nuclear
Tuesday, April 26, 2011
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, April 19, 2011
3:30 PM
Physics Building, Room 204

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"Molecular Breast Imaging Tomosynthesis"


Zongyi Gong , University of Virginia
[Host: Mark Williams]
ABSTRACT:
In 2-D Mammography, breast tissues are superimposed in single projection image thereby possibly masking small cancer. X-ray breast tomosynthesis (XBT) is a technique for reducing this problem by providing a 3-D image. However, it still provides only anatomic (structural) information. Since cancerous and harmless breast masses (lesions) often have similar structures, distinguishing them using structural imaging alone is difficult. The task of distinguishing between benign and malignant breast lesions can be significantly aided by taking advantage of the differences in their biological (functional) characteristics. Molecular breast imaging (MBI) is a recent technique that uses intravenously injected compounds (tracers) that are taken up to a much greater degree by malignant lesions than benign ones. By attaching a radioisotope atom to these tracer molecules they can give off a signal that can be detected by specially designed cameras placed near the breast. These cameras permit functional imaging of the entire breast and have resulted in reliable detection of tumors less than 1 cm in size. Nevertheless, similar to Mammography, the 2-D nature of MBI prevents any depth information of lesions from being obtainable. Moreover, the correction for gamma signal attenuation through the breast is virtually impossible in MBI. Our group is developing a unique dual modality tomographic (DMT) breast scanner that combines x-ray tomosynthesis and 3-D MBI tomosynthesis (MBIT) on a single integrated gantry. This talk will focus on the functional part. Specifically, image acquisition, reconstruction and restoration in MBIT will be covered.
Joint HEP/Nuclear Seminar
Tuesday, April 12, 2011
3:30 PM
Physics Building, Room 204

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"Second-Order Relativistic Hydrodynamics"


Guy Moore , McGill
[Host: Peter Arnold]
ABSTRACT:
Hydrodynamics is the universal theory describing the behavior of fluids when their spacetime variation is on scales longer than any microphysical scale in the fluid. Relativistic hydro has applications in heavy ion collisions and early Universe cosmology, and has seen a surge of interest due to heavy ion experiments and theoretical developments in AdS/CFT. I will explain what second order hydrodynamics is and why it is the minimum theory to study in the relativistic case. Then I discuss some limitations of the theory, including a new bound on how small the viscosity can be and a complication in the rigorous definition of the viscous relaxation time τπ.
SLIDESHOW:
Nuclear
Tuesday, April 5, 2011
3:30 PM
Physics Building, Room 204

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RESERVED
Nuclear
Tuesday, March 29, 2011
3:30 PM
Physics Building, Room 204

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Available
Nuclear
Tuesday, March 22, 2011
3:30 PM
Physics Building, Room 204

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"HAPPEX III Results: Measurement of the nucleon strange form factor at high Q2"


Rupesh Silwal , University of Virginia
[Host: Kent Paschke ]
ABSTRACT:
The bare mass of the three valance quarks only makes up ~ 1% of the proton mass, the rest is a sea of gluons, quarks and anti-quarks, which is dominated by the up, down and strange quarks. From the quark model, one might naively expect that the electromagnetic form factors are determined only by the valence quarks, with no contribution from the strange sea quarks. But, existing data suggesting a non-zero strange quark contribution to these form factors at high Q2 has been a topic of great interest. A new measurement of the strange quark vector form factors by the HAPPEX III collaboration is discussed.
SLIDESHOW:
Nuclear
Tuesday, March 15, 2011
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, March 1, 2011
3:30 PM
Physics Building, Room 204

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Available
Nuclear
Tuesday, February 22, 2011
3:30 PM
Physics Building, Room 204

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Available
Nuclear
Tuesday, February 15, 2011
3:30 PM
Physics Building, Room 204

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Available
Nuclear
Tuesday, February 8, 2011
3:30 PM
Physics Building, Room 204

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Special Colloquium
Nuclear
Tuesday, February 1, 2011
3:30 PM
Physics Building, Room 204

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Reserved for AMO Seminar
Nuclear
Tuesday, January 25, 2011
3:30 PM
Physics Building, Room 204

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Available
Nuclear
Tuesday, December 14, 2010
3:30 PM
Physics Building, Room 204

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RESERVED
Nuclear
Tuesday, December 7, 2010
3:30 PM
Physics Building, Room 204

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"Polarized Protons and Siberian Snakes"


Mei Bai , Brookhaven National Laboratory
[Host: Don Crabb]
SLIDESHOW:
Nuclear
Tuesday, November 30, 2010
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, November 23, 2010
3:30 PM
Physics Building, Room 204

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"Proton Form Factors: Recent Developments"


Andrew Puckett , Los Alamos Nuclear Laboratory
[Host: Nilanga Liyanage]
ABSTRACT:
The elastic electromagnetic form factors of the nucleon are among the most important observables characterizing its structure. Accurate knowledge of the proton form factors at large momentum transfers is required to test predictions of perturbative QCD, to constrain the nucleon Generalized Parton Distributions (GPDs), and to determine the nucleon's model-independent transverse charge and magnetization densities at small impact parameters. Through their relationship to GPDs, the nucleon form factors are also relevant to the nucleon spin puzzle, helping to evaluate Ji's angular momentum sum rule. In this seminar, I will present and discuss the results of recent recoil polarization measurements of the proton electric-to-magnetic form factor ratio. These results extend the momentum transfer reach of the method to Q2=8.5 GeV2, an increase of more than 50%. Additionally, our precise measurements at Q2=2.5 GeV2 will constrain models of multi-photon exchange effects believed responsible for the discrepancy between the Rosenbluth and polarization experiments.
SLIDESHOW:
Nuclear
Tuesday, November 16, 2010
3:30 PM
Physics Building, Room 204

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RESERVED
Nuclear
Tuesday, November 9, 2010
3:30 PM
Physics Building, Room 204

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Available
Nuclear
Tuesday, November 2, 2010
3:30 PM
Physics Building, Room 204

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Available
Nuclear
Tuesday, October 26, 2010
3:30 PM
Physics Building, Room 204

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Available
Nuclear
Tuesday, October 19, 2010
3:30 PM
Physics Building, Room 204

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RESERVED
Nuclear
Monday, October 18, 2010
3:30 PM
Physics Building, Room 204

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"The helicity asymmetry measurements for π 0 photoproduction with FROST at Jlab"


Hideko Iwamoto , George Washington University
[Host: Blaine Norum]
ABSTRACT:
One of the longstanding unsolved problem in the nuclear physics is that of the nucleon resonances N* and Δ*. The lifetime of these intermediate states is very short since they decay strongly. Their parameters, mass, width, and coupling constants to various decay modes are not well known. To solve this problem, double polarization experiments are considered to be a very effective tool. I will present the preliminary result of the helicity asymmetry “E” for γp → π 0 p channel from the first double polarization experiment at Jefferson Lab and compare this result with the prediction of theoretical models.
SLIDESHOW:
Nuclear
Wednesday, October 13, 2010
3:30 PM
Physics Building, Room 204

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ABSTRACT:
The quest for an understanding of the internal dynamics of the most fundamental systems in nature, the Hadron, continues. The theory of Quantum Chromodynamics, developed to describe these systems, explains many of the interactions which occur in the Hadron. This theory however cannot presently be solved analytically in the low-energy regime, the realm of non-perturbative QCD. Therefore in the place of these solutions, models of the baryon are used which treat the baryon as a system of three constituent quarks. These models however predict an excited baryon spectrum that has a higher density of states than that which has been observed experimentally. This is the so-called “missing resonance” problem. With the ultimate goal of finding evidence for the existence (or non-existence) of these resonances, quantities called “polarization observables” can be measured. These quantities which occur when the constraint of polarization is imposed on the reactions are highly sensitive to resonance production. In recent years, both single- and double-polarization experiments have been carried out at Jefferson Lab in Newport News, Virginia with the goal of resolving this missing resonance problem. One such polarized photoproduction experiment used linearly polarized photons incident on an unpolarized LH2 target. The analysis of a double meson final state from this polarized photoproduction data utilizing the power of a kinematic fitter has the ability to make highly accurate measurements of these observables. The analysis of γ p → p π + π - reactions and the extraction of two such observables, Is and Ic, is discussed.
SLIDESHOW:
Nuclear
Tuesday, October 5, 2010
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, September 28, 2010
3:30 PM
Physics Building, Room 204

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Available
Nuclear
Tuesday, September 21, 2010
3:30 PM
Physics Building, Room 204

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RESERVED
Nuclear
Tuesday, September 14, 2010
3:30 PM
Physics Building, Room 204

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"Radiation Safety Training"


Deborah Steva & Greg Payne , UVA Office of Environmental Health and Safety
[Host: Blaine Norum]
ABSTRACT:
All personnel who might want to use radioactive sources or other radioactive material, or want to work in areas where such materials are used, are required to obtain certification from the Office of Environmental Health and Safety. Deborah and Greg will present the required Radiation Safety Training Course leading to this certification. Anyone who may want to use radioactive material or work in an area where such material is used should attend this course.
Nuclear
Tuesday, September 7, 2010
3:30 PM
Physics Building, Room 204

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RESERVED
Nuclear
Tuesday, August 31, 2010
3:30 PM
Physics Building, Room 204

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Available
Nuclear
Tuesday, August 24, 2010
3:30 PM
Physics Building, Room 204

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Available
Nuclear
Tuesday, May 4, 2010
3:30 PM
Physics Building, Room 204

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"Physically motivated GPD parametrization"


J. Osvaldo Gonzalez H. , University of Virginia
[Host: Don Crabb]
SLIDESHOW:
Nuclear
Tuesday, April 27, 2010
3:30 PM
Physics Building, Room 204

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RESERVED
Nuclear
Tuesday, April 20, 2010
3:30 PM
Physics Building, Room 204

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"DVCS on the Deuteron"


Nick Kvaltine , University of Virginia
[Host: Don Crabb]
SLIDESHOW:
Nuclear
Tuesday, April 13, 2010
3:30 PM
Physics Building, Room 204

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"Test of the Equivalence Principle in the Laboratory"


Stephan Schlamminger , University of Washington
[Host: Stefan Baessler]
ABSTRACT:
The equivalence principle (EP) states that in a uniform gravitational field all bodies fall with the same acceleration regardless of their mass and internal structure. The equivalence principle is the underlying foundation of General Relativity, our current theory of gravity. Despite the fact that General Relativity has passed many precision experimental tests, it is fundamentally incompatible with the quantum nature of the standard model. Modern theories, like string theory and quantum gravity, predict violations of the equivalence principle. In the experiments conducted at the University of Washington a composition dipole is suspended from a thin fiber in a vacuum vessel that rotates with constant rate. A violation of the equivalence principle would yield to a differential acceleration of the two materials to a source mass located to the side of this torsion balance. Any differential acceleration can be detected as a sinusoidal excursion of the torsion pendulum at the rotation period. In this talk I will present measurements of the differential acceleration with an uncertainty of 3 fm/s2. These measurements set new limits on equivalence principle violating interactions between the composition dipole and a variety of sources.
SLIDESHOW:
Nuclear
Thursday, April 8, 2010
2:00 PM
Physics Building, Room 313

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"Recent results from the Relativistic Heavy Ion > Collider, and prospects for the LHC"


Peter Steinberg , Brookhaven National Lab
[Host: Donal Day]
Nuclear
Tuesday, April 6, 2010
3:30 PM
Physics Building, Room 204

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"The Science and Realization of the Electron Ion Collider"


Abhay Deshpande , Stonybrook University/RBRC
[Host: Don Crabb]
SLIDESHOW:
Nuclear
Tuesday, March 30, 2010
3:30 PM
Physics Building, Room 204

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"Measurement of Nucleon Strange Form Factors at High Q2"


Rupesh Silwal , University of Virginia
[Host: Kent Paschke]
SLIDESHOW:
Nuclear
Tuesday, March 23, 2010
3:30 PM
Physics Building, Room 204

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Reserved
[Host: Craig Dukes]
Nuclear
Tuesday, March 16, 2010
3:30 PM
Physics Building, Room 204

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Available
Nuclear
Tuesday, March 2, 2010
3:30 PM
Physics Building, Room 204

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RESERVED
Nuclear
Tuesday, February 16, 2010
3:30 PM
Physics Building, Room 204

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"Spin Structure of the Deuteron New Results from CLAS"


Nevzat Guler , Old Dominion University
[Host: Blaine Norum]
ABSTRACT:
Double spin asymmetries for the proton and the deuteron have been measured in the EG1b experiment using the CLAS detector at Jefferson Lab. Longitudinally polarized electrons at energies 1.6, 2.5, 4.2 and 5.7 GeV were scattered from longitudinally polarized NH 3 and ND 3 targets. The double spin asymmetry Ak has been extracted from these data as a function of Q 2 and W with unprecedented precision. The virtual photon asymmetry A 1 and the spin structure function g 1 can be calculated from these measurements by using parameterizations to the world data for the virtual photon asymmetry A 2 and the unpolarized structure functions F 1 and R. The large kinematic coverage of the experiment (0.05 GeV 2 < Q 2 < 5.0 GeV 2 and 1.08 GeV < W < 3.0 GeV) helps us to better understand the spin structure of the nucleon, especially in the transition region between hadronic and quark-gluon degrees of freedom. The results from EG1b combined with other experiments provide a good description of the virtual photon asymmetries making their parameterizations possible in a large kinematic range. In this talk, the results on A 1 , g 1 and the first moment Γ 1 1 of the deuteron will be presented. The parametrization efforts on the asymmetries and the spin structure functions will be discussed. The neutron spin structure function, extracted from the combined proton and deuteron data, will be shown.
SLIDESHOW:
Nuclear
Tuesday, February 2, 2010
3:30 PM
Physics Building, Room 204

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RESERVED
Nuclear
Tuesday, January 26, 2010
3:30 PM
Physics Building, Room 204

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ABSTRACT:
The NPDGamma experiment aims to measure the correlation between the neutron spin and the direction of the emitted photon in neutron-proton capture. A parity violating asymmetry from this process can be directly related to the strength of the hadronic weak interaction between nucleons. The first phase of the experiment was completed in 2006 at LANSCE. The methodology will be discussed and preliminary results will be presented. The next run will start in early 2010 at the SNS at ORNL with several improvements, which will be discussed. The upcoming run will yield a measurement with a projected statistical error 1x10 -8 . This will allow the results to be compared meaningfully with theoretical predictions
Nuclear
Tuesday, December 8, 2009
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, December 1, 2009
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, November 24, 2009
3:00 PM
Physics Building, Room 313

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"The GDH Experiment at MAMI"


OLIVER JAHN , University of Mainz
[Host: Blaine Norum]
ABSTRACT:
The GDH sum rule connects ground state properties of the nucleon with helicity-dependent cross sections. To investigate these cross sections on the deuteron, experiments have been carried out by the A2-Collaboration at the Mainz Microtron (Germany) in 1998 and in 2003, using circularly polarized photons on a polarized d-butanol target. The latest analysis results and the status of the GDH experiment with the Crystal Ball detector are reported.
Nuclear
Tuesday, November 17, 2009
3:30 PM
Physics Building, Room 204

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RESERVED
Nuclear
Tuesday, November 10, 2009
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, November 3, 2009
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, October 20, 2009
3:30 PM
Physics Building, Room 204

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RESERVED
Nuclear
Tuesday, October 13, 2009
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, September 29, 2009
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, September 22, 2009
3:30 PM
Physics Building, Room 204

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RESERVED
Nuclear
Tuesday, September 15, 2009
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, September 8, 2009
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, September 1, 2009
3:30 PM
Physics Building, Room 204

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Available
Nuclear
Tuesday, August 25, 2009
3:30 PM
Physics Building, Room 204

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RESERVED
Nuclear
Tuesday, April 28, 2009
3:30 PM
Physics Building, Room 204

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SLIDESHOW:
Nuclear
Tuesday, April 21, 2009
3:30 PM
Physics Building, Room 204

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"Probing 3He Ground-State in Spin-Asymmetry Measurements in Jefferson Lab"


Ge Jin , University of Virginia
[Host: Blaine Norum]
ABSTRACT:
This is the only Jefferson Lab polarized 3He experiment which is seeking to better understand the 3He system, as opposed to using it as an effective neutron target, by measuring double-polarized asymmetries in the 3He(e,e'd) reaction which are believed to be a probe particularly sensitive to the details of the 3He system. Major theoretical advances have been made in the Faddeev calculations of the Bochum/Krakow and Hannover groups, resulting in quite distinct descriptions of these observables. This development has important implications for experiments using 3He as an effective neutron target.
SLIDESHOW:
Nuclear
Tuesday, April 14, 2009
3:30 PM
Physics Building, Room 204

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SLIDESHOW:
Nuclear
Tuesday, April 7, 2009
3:30 PM
Physics Building, Room 204

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Reserved for CM Seminar
Nuclear
Tuesday, March 31, 2009
3:30 PM
Physics Building, Room 204

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"Searching for Double Beta Decay with the Enriched Xenon Observatory"


Lisa Kaufman , University of Maryland
[Host: Kent Paschke ]
ABSTRACT:
An observation of neutrinoless double beta decay would have significant impact on our understanding of the lepton sector of the Standard Model. First, neutrinoless double beta decay could shed light on the absolute mass scale of the neutrino mass spectrum, a quantity which cannot be constrained by neutrino oscillation experiments. Second, double beta decay is only allowed if the neutrino and anti-neutrino are identical which is a basic prediction of many extensions of the Standard Model including many grand unified theories. The Enriched Xenon Observatory (EXO) is developing sensitive searches of double beta decay using Xenon-136. The first phase of the experiment, called EXO-200, is in the final stages of assembly in the WIPP underground facility in Carlsbad, NM and will be by far the largest double beta decay experiment ever attempted. The current status of the EXO-200 experiment will be presented.
Nuclear
Tuesday, March 24, 2009
3:30 PM
Physics Building, Room 204

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"Nucleon Form Factors from Lattice QCD"


Meifeng Lin , MIT
[Host: Chris Dawson]
ABSTRACT:
First-principles calculations of the nucleon form factors and generalized form factors have been made possible by employing the lattice QCD techniques. Together with the experimental efforts, lattice results for the nucleon form factors have deepened our understanding of the internal structure of the nucleon, such as the charge and current distributions, and the spin decomposition of the nucleon. In this talk, I will present some recent lattice QCD results for the nucleon form factors using a five-dimensional chirally symmetric fermion action. I will also address some challenges faced by modern lattice form factor calculations.
Nuclear
Monday, March 23, 2009
3:30 PM
Physics Building, Room 204

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"In a muon's lifetime: From Fermi's constant to "calibrating" the sun"


Peter Winter , University of Illinois at Urbana-Champaign
[Host: Don Crabb]
ABSTRACT:
The muon group at Illinois is performing three experiments at the Paul Scherrer Institute all measuring the muon lifetime with high precision. The MuLan experiment uses a simple soccer-ball like scintillator array to detect the decay positrons. We collected twice 10 12 muon decays in two different target materials to obtain the final precision of 1 ppm which will give a 20 times better determination of the Fermi constant G F . A first result was recently published [1] which already improved the precision of G F to 5 ppm. The muon capture experiment MuCap uses a negative muon beam stopped in a time projection chamber as an active target filled with ultra-pure hydrogen gas. The elementary capture process μ - +p → n+ ν offers a rare (0.15%) but additional disappearance channel. The measured difference of the positive and negative muon's lifetime determines the rate of the capture process to a final precision of 1%. This can be used to derive an improved value of the proton's pseudoscalar form factor g P to 7% precision. A first result gP = 7.3  1.1 has been published [2]. This is a first precise, unambigous determintation of gP and an important test of QCD symmetries. Recently, we started a new experiment, MuSun [3], that will start a first commissioning run at the end of 2008. Here, a measurement of the μ - +d → n+n+ ν provides a benchmark of the understanding of weak processes in the two nucleon-system. It was shown, that other weak reactions involving the two nucleon system (pp → de + ν or ν +d reactions) are related to the same low-energy constant, characterizing the two nucleon system at short distances. This constant is not well constrained and therefore the MuSun experiment comes closest to calibrating these basic astrophysical reactions under terrestrial conditions. [1] Phys. Rev. Lett. 99, 032001 (2007) [2] Phys. Rev. Lett. 99, 032002 (2007) [3] http://www.npl.uiuc.edu/exp/musun/documents/prop07.pdf
SLIDESHOW:
Nuclear
Tuesday, March 17, 2009
3:30 PM
Physics Building, Room 204

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Reserved for CMP seminar
Nuclear
Tuesday, March 10, 2009
3:30 PM
Physics Building, Room 204

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RESERVED
Joint Nuclear and High Energy Seminar
Monday, March 9, 2009
3:30 PM
Physics Building, Room 204

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"The MEG lepton flavor violation search: challenges and solutions"


Stefan Ritt , Paul Scherrer Institute
[Host: Dinko Pocanic ]
ABSTRACT:
The talk presents an overview and status report of the MEG experiment at PSI, Switzerland, which searches for the decay Mu -> e Gamma at the 10^(-13) level. The motivation for the experiment is discussed and compared with other Lepton Flavor Violating processes, such as Mu A -> eA conversion. To accommodate the extremely high demands regarding pile-up suppression, timing resolution, and versatility, a special waveform digitizing technique was designed and implemented in the MEG experiment. It relies on the Domino Ring Sampling chip (DRS), capable of digitizing 8 channels with 5 GHz and 12 bits effective resolution on a single radiation hard CMOS chip. The DRS chip is currently used in the MEG experiment to digitize 2000 drift chamber channels and 1000 photomultiplier channels, eliminating the need for traditional ADCs and TDCs. Techniques used in MEG for waveform processing (e.g., data compression, pulse shape discrimination, and crosstalk elimination) may have applications in other rare decay experiments, and in cosmic ray astronomy.
SLIDESHOW:
Nuclear
Tuesday, February 24, 2009
3:30 PM
Physics Building, Room 204

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"Extracting the Gluon Piece of the Spin Puzzle: New Inclusive Jet Results from STAR "


Renee Fatemi , University of Kentucky
[Host: Don Crabb]
SLIDESHOW:
Nuclear
Tuesday, February 17, 2009
3:30 PM
Physics Building, Room 204

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SLIDESHOW:
Nuclear
Tuesday, February 10, 2009
3:30 PM
Physics Building, Room 204

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"Electron Beam Polarimetry for Future PV Experiments at JLab"


Eugene Chudakov , J. Lab
[Host: Don Crabb]
ABSTRACT:
A new generation of ultra-precise measurements of parity-violation (PV) effects in electron scattering at 12 GeV at JLab is being currently developed. These experiments will require an improvement in beam polarimetry accuracy, by a factor of 2 to 3 in comparison with the present most accurate measurements. I will present an outline of the planned PV experiments, describe the existing polarimetry methods, and discuss a proposal to improve considerably the accuracy of polarimetry based on Moller scattering. It is proposed to use polarized atomic hydrogen gas, stored in an ultra-cold magnetic trap, as the polarimeter target. Such a target of practically 100% polarized electrons could provide a systematic accuracy better than 0.5%. Although such traps have been built for particle physics applications, the storage cell has not been used so far as the target in a high power beam. Possible impacts the CEBAF beam can make on such a target will be discussed, including heating by ionization losses and the impact of the beam electromagnetic (RF) radiation.
SLIDESHOW:
Nuclear
Tuesday, February 3, 2009
3:30 PM
Physics Building, Room 204

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RESERVED
Nuclear
Tuesday, January 27, 2009
3:30 PM
Physics Building, Room 204

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"Precision Measurement of a and b in Neutron Beta Decay"


Pete Alonzi , University of Virginia
[Host: Don Crabb]
ABSTRACT:
Using a novel 4π detector the Nab collaboration intends to measure a, the electron-neutrino correlation parameter, and b, the Fierz interference term, in neutron beta decay. The Nab experiment will be conducted in the Fundamental Neutron Physics Beamline at the Spallation Neutron Source in Oak Ridge, TN. I will present the design and simulation of the Electro-Magnetic Spectrometer which will be used to confine the decay products and shepherd them to the detector.
SLIDESHOW:
Nuclear
Tuesday, January 20, 2009
3:30 PM
Physics Building, Room 204

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RESERVED
Nuclear
Wednesday, January 14, 2009
3:30 PM
Physics Building, Room 204

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"Precise Measurement of the π → e υ Branching Ratio"


Anthony Palladino , University of Virginia
[Host: Don Crabb]
ABSTRACT:
The PEN experiment aims to measure the semileptonic decay π → eν(γ)(πe2 decay) branching ratio at PSI, with an ncertainty of ΔB/B∼5×10-4,or better, using a large-angle detector system featuring a pure CsI calorimeter. This experiment will give a stringent test of lepton universality. Preliminary results from a basic level analysis of data from the first two developmental runs will be discussed. These results, coupled with a discussion of experimental techniques, such as the use of a segmented active degrader and target waveform digitization, will demonstrate our ability to control systematic uncertainties in the experiment.
SLIDESHOW:
Nuclear
Tuesday, January 13, 2009
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, December 2, 2008
3:30 PM
Physics Building, Room 204

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"Electroproduction of Neutral Pions from the Proton near Threshold"


Khem Chirapatpimol , University of Virginia
[Host: Don Crabb]
SLIDESHOW:
Nuclear
Tuesday, November 25, 2008
3:30 PM
Physics Building, Room 204

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RESERVED
Nuclear
Tuesday, November 18, 2008
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, November 11, 2008
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, November 4, 2008
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, October 28, 2008
3:30 PM
Physics Building, Room 204

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RESERVED
Nuclear
Tuesday, October 21, 2008
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, October 14, 2008
3:30 PM
Physics Building, Room 204

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"Progress in the Determination of Polarized PDFs and Higher Twist"


D. Stamenov , Institute for Nuclear Research and Nuclear Energy, Bulgaria
[Host: D. G. Crabb]
ABSTRACT:
The impact of very precise CLAS and COMPASS g 1 /F 1 data on the polarized parton densities and higher twist effects is discussed. It is demonstrated that the inclusion of the low Q 2 CLAS data in the NLO QCD analysis of the world DIS data improves essentially our knowledge of HT corrections to g 1 and does not affect the central values of PDFs, while the large Q 2 COMPASS data influence mainly the strange quark and gluon polarizations, but practically do not change the HT corrections. The uncertainties in the determination of polarized parton densities are significantly reduced due to both of the data sets. These results strongly support the QCD framework, in which the leading twist NLO pQCD contribution is supplemented by higher twist terms of O(Λ 2 /Q 2 ). Different solutions for the polarized gluon density, as well as the present status of the proton sum rule are also discussed.
Nuclear
Tuesday, October 7, 2008
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, September 30, 2008
3:30 PM
Physics Building, Room 204

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RESERVED
Nuclear
Tuesday, September 23, 2008
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, September 16, 2008
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, September 9, 2008
3:30 PM
Physics Building, Room 204

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Available
Nuclear
Tuesday, September 2, 2008
3:30 PM
Physics Building, Room 204

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RESERVED
Nuclear
Tuesday, August 26, 2008
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, May 6, 2008
3:30 PM
Physics Building, Room 313

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"Using Semileptonic Decays to search for two gluon couplings in the Eta-prime "


Richard Gray , Cornell University
[Host: Kent Paschke]
ABSTRACT:
Large branching fractions for hadronic B decays involving the eta^prime (1997) and also in the B semileptonic decay to the eta^prime (2006) could potentially be caused by the extra 2-gluon couplings from the singlet component of the eta^prime meson. Now, for CLEO-C, we look to semileptonic decays of the D meson to the eta^prime to see if there is evidence for enhancement there as well. We make improvements to the “neutrino reconstruction” method used to study B decays, and find that the new algorithm can also be used to simultaneously measure a large number of D hadronic decays as well.
SLIDESHOW:
Nuclear
Tuesday, April 29, 2008
3:30 PM
Physics Building, Room 204

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"Next Solid Polarized Target Experiment at JLAB: Accessing the nucleon spin structure"


Jonathan Mulholland , University of Virginia
[Host: Donal Day]
SLIDESHOW:
Nuclear
Tuesday, April 22, 2008
3:30 PM
Physics Building, Room 204

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"Deuteron Photodisintegration (d( γ 1 n)p) at HI γ S"


Serpil Kucuker , University of Virginia
[Host: Blaine Norum ]
SLIDESHOW:
Nuclear
Thursday, April 17, 2008
4:00 PM
Physics Building, Room 204

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"The Spin Asymmetry on the Nucleon Experiment (SANE) at Jefferson Lab's Hall C"


James Maxwell , University of Virginia
[Host: Donal Day]
ABSTRACT:
The Spin Asymmetry on the Nucleon Experiment (SANE) will employ a revolutionary increase in Figure of Merit to obtain precise gp2 and Ap1 results at high Bjorken x. Using the highest available JLab beam energy, a 194 msr electromagnetic calorimeter will view the UVa polarized NH3 target at 8.5 times 10^34 proton luminosity. The large Bjorken x region provides an important view on proton structure where the sea quarks have been stripped away. Using measurements of these ``naked protons'' is crucial for the understanding of strong QCD and can provide a connection between experimentally measured moments of polarized structure functions and quark matrix elements calculated in lattice QCD. The experiment is scheduled to begin installation in June, and will begin taking data in October, using JLab's 5.9 GeV polarized electron beam. We will discuss the physics motivation for SANE, as well as the current status of the preparations and expected results.
SLIDESHOW:
Nuclear
Tuesday, April 8, 2008
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, April 1, 2008
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, March 25, 2008
3:30 PM
Physics Building, Room 204

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"Design of a Hybrid 3 He Polarizer: Measurement Techniques and Construction"


Karen Mooney , University of Virginia
[Host: Gordon Cates]
ABSTRACT:
A Hybrid 3 He Polarizer is being constructed for use by the Center for InVivo Hyperpolarized Gas MR Imaging at the University of Virginia Health System. It will take advantage of the Hybrid Spin Exchange Optical Pumping, and it will be calibrated using a combination of Adiabatic Fast Passage NMR and Electron Paramagnetic Resonance. These techniques will be detailed, and the construction progress will be summarized.
SLIDESHOW:
Nuclear
Tuesday, March 18, 2008
3:30 PM
Physics Building, Room 204

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"Production and Optimization of Hybrid Spin Exchange Optically Pumped 3He Cells"


Peter Dolph , University of Virginia
[Host: Gordon Cates]
ABSTRACT:
Hybrid spin exchange optical pumping consistently outperforms pure alkali SEOP. Hybrid cells contain an alloy of potassium and a small amount of rubidium, whereas conventional cells contain a single species of metal, typically Rb. K-3He spin exchange is more efficient than Rb-3He. Consequently, less laser power is required to achieve a higher noble gas polarization with the benefit of a shorter polarization time. The hybrid technique has been successfully employed in the large scale production of target cells for use in nuclear physics experiments and shows great potential for use in medical imaging. The production of hybrid alloys, optimization, and results will be discussed.
SLIDESHOW:
Nuclear
Tuesday, March 11, 2008
3:30 PM
Physics Building, Room 204

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"Cold and Ultra-cold neutron studies at IUCF"


Yunchang Shin , Indiana University /IUCF
[Host: Stefan Baessler]
ABSTRACT:
The Low Energy Neutron Source at Indiana University is a University-based long-pulsed source that makes use of a coupled solid methane moderator operating at temperatures below 10K. I will present recent results in which the moderator performance is compared to the predictions from our recently developed model for methane dynamics in the low temperature (Phase II). I will also present the UCN production in solid oxygen involving magnon (spin wave) exchanges which is fundamentally different from the well-known phonon mechanism in solid deuterium.
SLIDESHOW:
Nuclear
Tuesday, February 26, 2008
3:30 PM
Physics Building, Room 204

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"Chiral extrapolation of nucleon magnetic form factors"


Ping Wang , JLAB
[Host: Simonetta Liuti]
ABSTRACT:
The extrapolation of nucleon magnetic form factors calculated within lattice QCD is investigated within a framework based upon heavy baryon chiral effective-field theory. All one-loop graphs are considered at arbitrary momentum transfer and all octet and decuplet baryons are included in the intermediate states. Finite range regularisation is applied to improve the convergence in the quark-mass expansion. The resulting values of the form factors at the physical pion mass are in good agreement with the experimental data.
SLIDESHOW:
Nuclear
Tuesday, February 19, 2008
3:30 PM
Physics Building, Room 204

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Reserved for Colloquium
Nuclear
Tuesday, February 12, 2008
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, February 5, 2008
3:30 PM
Physics Building, Room 204

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Available
Nuclear
Tuesday, January 29, 2008
3:30 PM
Physics Building, Room 204

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Available
Nuclear
Tuesday, January 22, 2008
3:30 PM
Physics Building, Room 204

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Available
Nuclear
Monday, January 14, 2008
3:30 PM
Physics Building, Room 204

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"TBA"


Anthony Palladino , University of Virginia
[Host: Don Crabb]
Nuclear
Tuesday, December 4, 2007
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, November 27, 2007
3:30 PM
Physics Building, Room 204

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"Pentaquarks: facts, mysteries and prospects."


Moskov Amarian , ODU
[Host: Donal Day]
ABSTRACT:
I will give an introduction to the pentaquarks, possible five quark baryons. Quantum Chromodynamics does not forbid existence of such a states, however experimental evidence for their existence is controversial. The whole sitation becomes even more complicated recently as some experiments claiming the discovery of pentaquarks did not see it in a repeated high statistics data set and therefore set up an upper limits for the cross section for the production of the Theta+ baryon on the order of a few nano barn. I will discuss this and also the possibility on how one can increase the sensitivity of the measurement using Quantum Mechanical interference with other strong production channels leading to the same final state.
SLIDESHOW:
Nuclear
Tuesday, November 13, 2007
3:30 PM
Physics Building, Room 204

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"The Spin-Structure of the Nucleon"


Elke-Caroline Aschenauer , JLAB
[Host: Donal Day]
ABSTRACT:
The question after the individual parton (quarks and gluons) contributions to the spin of the nucleon is even after 20 years of experimental efforts not yet solved. After several very precise measurements in polarized deep inelastic scattering it is clear, that the spin of the nucleon can not be explained by the contribution of the quarks alone. This is affirmed by the newest results from COMPASS, HERMES and JLAB on the inclusive spin structure function g1 and on the individual contributions from the different quark flavors from semi-inclusive deep inelastic scattering data. Recently COMPASS and HERMES have started to measure the gluon polarization by isolating the photon gluon fusion process in semi-inclusive deep inelastic scattering; latest results on the contribution of the gluons to the nucleon spin from these measurements and RHIC will be discussed. The clear experimental evidence of exclusive reactions, especially DVCS, allows in the formalism of generalised parton distributions the study of an other component of the nucleon spin the orbital angular momentum. The most recent results on indications of the size of the orbital angular momentum of quarks will be presented.
SLIDESHOW:
Nuclear
Tuesday, November 6, 2007
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, October 30, 2007
3:30 PM
Physics Building, Room 204

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"Pentaquarks: much ado about nothing?"


Wouter Deconinck , University of Michigan
[Host: Kent Paschke]
ABSTRACT:
In 2003 new experimental evidence was presented for the observation of the exotic baryon Θ + (1540) with a minimal quark content $uuddar{s}$. Quickly more than ten nuclear and high energy physics experiments reported positive results, apparently confirming the existence of the Θ + (1540), but all suffered from low statistical precision. An increasing number of null results started to appear, seemingly in contradiction with the positive sightings. Now the null results dominate the positive results, often with impressive statistical precision, and cast doubt on the existence of the Θ + (1540). The experimental status will be discussed, including some recent positive results. The past contributions and ongoing efforts of the Hermes experiment will be highlighted.
SLIDESHOW:
Nuclear
Tuesday, October 23, 2007
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, October 16, 2007
3:30 PM
Physics Building, Room 204

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Available
Nuclear
Tuesday, October 9, 2007
3:30 PM
Physics Building, Room 204

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RESERVED
Nuclear
Tuesday, October 2, 2007
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, September 25, 2007
3:30 PM
Physics Building, Room 204

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"The pion form factor"


Tanja Horn , JLAB
[Host: Donal Day]
ABSTRACT:
The pion charge form factor, F π , is the fundamental interest in the study of the quark-gluon structure of hadrons. The relatively simple < qq > valence structure makes the pion an ideal test case for all models of hadronic structure. Experimentally, the measurement of the pion form factor poses special challenges. The technique utilizes a precision Rosenbluth seperation of the p(e,e' π + )n reaction at low -t. F π is then extracted from the separated σ L cross sections with the aid of a model. Over the past several years, we have carried out two experiments at Jefferson Lab (JLab) to measure F π over a kinematic range of Q 2 = 0.6-2.45 GeV 2 . These measurements are planned to be extended to higher Q 2 with the completion of the JLab 12 GeV upgrade. These data would challenge QCD based calculations in the most rigorous manner. The recent JLab results will be presented and compared to a variety of model calculations, and the future outlook will be discussed.
Nuclear
Tuesday, September 18, 2007
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, September 11, 2007
3:30 PM
Physics Building, Room 204

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RESERVED
Nuclear
Tuesday, September 4, 2007
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, August 28, 2007
3:30 PM
Physics Building, Room 204

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Available
Special Colloquium
Tuesday, May 1, 2007
3:30 PM
Physics Building, Room 204

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"A new tool-box for hadronic studies: Optics and Self-Organizing Networks"


Simonetta Liuti , University of Virginia
[Host: Blaine Norum]
ABSTRACT:
Although Quantum Chromodynamics (QCD) is the acclaimed theory of the strong interactions, important longstanding questions still remain to be answered on the nature of confinement of quarks and gluons inside the proton, and on their dynamical contribution to the proton's mass and spin. Deeply Virtual Compton Scattering (DVCS) and Exclusive Meson Production provide alternative tools to purely inclusive reactions that have significantly improved our studies of hadronic structure. By allowing for an additional momentum transfer "t" to the proton besides the large momentum transfered in the deep inelastic collision, one can in principle simultaneously access the longitudinal momentum fraction of the quarks and their position inside the proton, providing 3D "images" of quarks in hadrons. The price one pays for the rich phenomenology accessible through DVCS is a dramatic increase in complexity, due to the enlarged phase space one needs to cover. A new approach is being developed based on Self-Organizing Maps (SOMs), broadly related to Neural Networks, that allows for extensive parameter searches and enables the user to directly control the data selection procedure. Finally, among a wide range of recently studied implications, the SOMs models are connected to complexity theory, leading to the possibility of studying emergent behaviors in the system's properties.
SLIDESHOW:
Nuclear
Tuesday, April 24, 2007
3:30 PM
Physics Building, Room 204

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"A Precision Measurement to Test Chiral QCD Dynamics"


Mitra Shabestari , University of Virginia
[Host: Donal Day]
ABSTRACT:
Experiment E04-007, in Hall A at Jefferson Lab, is a high precision measurement of the reaction P(e,e'P)π 0 from the threshold to 20MeV above, and Q 2 values between 0.04(GeV/c) 2 and 0.14(GeV/c) 2 . The near threshold cross sections are relatively small, which demand high resolution and as large acceptance as possible. Hall A, with the HRS and large acceptance BigBite spectrometer satisfies these requirements. I will talk about BigBite spectrometer, and also explain how the results of this experiment will provide a stringent test of chiral QCD.
Nuclear
Tuesday, April 17, 2007
3:30 PM
Physics Building, Room 204

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"Measurement of hyperpolarized gas diffusion at very short time scales"


Michael Carl , University of Virginia
[Host: Donal Day]
ABSTRACT:
Hyperpolarized 3 He diffusion MRI is a powerful tool to probe lung microstructure at a length scale inaccessible by conventional k-space MRI. For short diffusion times, ∆, time dependent diffusion measurements are sensitive to the surface to volume ratio (S/V) of the surrounding structure. Because of the high gas diffusivity (D Xe =0.14cm 2 /s, D He =0.88cm 2 /s) and the small size of alveoli (~200μm), measurement of S/V with the traditional single bipolar diffusion technique is challenging in the lung, since only small diffusion attenuation can be imparted within the short time scale regime (~200μs). Given the significance of short time scale diffusion in the assessment of lung microstructure, we developed a new technique that proves promising to enable such measurements.
Special Colloquium
Tuesday, April 10, 2007
3:30 PM
Physics Building, Room 204

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"Investigating Parity Violation in Neutron Decay "


Stefan Baessler , Johannes Gutenberg Universitat Mainz (Germany)
[Host: Blaine Norum]
ABSTRACT:
Precision measurements in neutron decay allow to determine the coupling constants of weak interaction and to test aspects of the Standard Model of Elementary Particle Physics. This is achieved in measurements of the lifetime of the neutron and of several angular correlations in the decay. In my talk I will mainly report about the experiences and results we gained with the spectrometers PERKEO and aSPECT.
Nuclear
Tuesday, March 20, 2007
3:30 PM
Physics Building, Room 204

 Slideshow (PDF)
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ABSTRACT:
The EG4 experiment at the Jefferson Lab (E12-06-109) studied the GDH (Gerasimov-Drell_Hearn) Sum Rule that relates the difference of the two photoabsorption cross-sections to the anomalous magnetic moment of the proton, deuteron and neutron in the real photon limit. In reality we try to approach the real photon limit by having the Q 2 very small. The experiment used a highly polarized electron beam and longitudinally polarized solid ammonia targets. The analysis to determine the deuteron target polarization using the data acquired from the NMR system will be shown with different analysis methods compared and further target polarization analysis via the scattering asymmetry method is also discussed.
SLIDESHOW:
Nuclear
Thursday, March 15, 2007
4:00 PM
Physics Building, Room 204

 Slideshow (PDF)
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"External Fields in Lattice Hadron Physics"


William Detmold , INT, U. of Washington
[Host: Hank Thacker ]
ABSTRACT:
Lattice QCD is a numerical method for solving the complicated dynamics of QCD in the non-perturbative, low energy regime, allowing computations of the spectrum and strong interactions of hadrons. To investigate the interactions of these hadrons with the remainder of the Standard Model (leptons and the electro-weak gauge bosons) and physics beyond the Standard Model, external operators must be included. This can be done by calculating hadron matrix elements with explicit operator insertions and generally also using external field techniques. In this second approach, the properties of hadrons are computed in an appropriate classical background field (e.g., electroweak) and their modification from the zero external field case determines the quantity of interest. I will discuss the advantages and disadvantages of this approach giving examples including the electromagnetic and spin polarisabilities of hadrons and the nuclear modification of parton distributions (the EMC effect).
SLIDESHOW:
Nuclear
Tuesday, March 13, 2007
3:30 PM
Physics Building, Room 204

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"Localization transition in QCD at nonzero temperature"


James Osborn , Boston University
[Host: Hank Thacker]
ABSTRACT:
Over 20 years ago Diakanov and Petrov suggested that the chiral phase transition in QCD might be similar to a metal-insulator transition based on the instanton description of the QCD vacuum. The arguments, however, are general and can be applied to other topological objects as well. I will review the proposed connection between QCD and a disordered medium and present some recent results from lattice QCD that are consistent with a localization transition in the lowest eigenmodes of the Dirac operator.
Nuclear
Thursday, March 1, 2007
4:00 PM
Physics Building, Room 204

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"Holography with backreacted flavor"


Diana Vaman , University of Michigan
[Host: Hank Thacker]
ABSTRACT:
The gauge/string holographic duality has opened a new window into the non-perturbative regime of gauge theories. I will present the construction of supergravity duals to N=2 supersymmetric gauge theories coupled with matter (quarks) in the fundamental representation of the gauge group. The supergravity solutions are obtained by taking the decoupling limit of D3/D7 (color/flavor) brane systems. The backreaction of the flavor branes needs to be accounted for, as it allows to go beyond the quenched approximation on the dual gauge theory side. I will give the spectrum of mesons (bound states of quark-anti quark pairs) and discuss the effect of the backreacted flavor. Lastly, I will present the supergravity dual to the finite temperature gauge theory. This corresponds to a backreacted non-extremal D3/D7 system. At finite temperature, the fundamental matter undergoes a first order phase transition. I will discuss this phase transition from the perspective of the supergravity dual.
Nuclear
Tuesday, February 27, 2007
3:30 PM
Physics Building, Room 204

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"The Kaon B-Parameter from Lattice QCD"


Chris Dawson , Brookhaven National Lab
[Host: Hank Thacker]
ABSTRACT:
I will discuss the calculation of the Kaon B-parameter, a measure of indirect CP-violation in the Standard Model, using Lattice QCD. In particular, I will talk about the use of the Domain Wall Fermion formulation of Lattice QCD, a formulation which has continuum-like symmetry properties at finite lattice spacing at the expense of the introduction of an additional, fifth, dimension.
Nuclear
Tuesday, February 20, 2007
3:30 PM
Physics Building, Room 204

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"Latest results on the low-energy search for new physics"


Ross Young , JLAB
[Host: Hank Thacker]
ABSTRACT:
The Standard Model has been enormously successful at predicting the outcomes of experiments in nuclear and particle physics. The search for new physical phenomena and a fundamental description of nature which goes beyond the Standard Model is driven by two complementary experimental strategies. The first is to build increasingly energetic colliders, such as the Large Hadron Collider (LHC) at CERN, which aim to excite matter into a new form. The second, more subtle approach, is to do precision measurements at moderate energies, where an observed discrepancy with the Standard Model will reveal the signature of these new forms of matter. Here we demonstrate that the latest measurements of the electroweak force severely constrain the possibility of physics beyond the Standard Model to above the TeV energy scale.
Nuclear
Wednesday, February 7, 2007
3:30 PM
Physics Building, Room 313

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"New Developments In Generalized Parton Distributions"


Swaolhin Tameja , Ecole Polytechnique
[Host: Simonetta Liuti]
Nuclear
Tuesday, February 6, 2007
3:30 PM
Physics Building, Room 204

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"Two-photon exchange in elastic electron-nucleon scattering"


Wally Melnitchouk , Jefferson Lab
[Host: Donal Day]
ABSTRACT:
The ratio of the electric to magnetic proton form factors has traditionally been determined using the Rosenbluth separation method, in which the ratio is extracted from the angular dependence of the cross section at fixed momentum transfer Q 2 . Measurements at JLab using the alternative, polarization transfer technique found a dramatically different behavior of the ratio compared with the Rosenbluth results. I discuss the resolution of this discrepancy by considering the effects of two-photon exchange in elastic e-p scattering, taking particular account of the nucleon's finite size. Contributions from excited nucleon intermediate states are also considered, and estimates given of two-photon exchange corrections to the form factors of the neutron and He-3.
Nuclear
Tuesday, December 5, 2006
3:30 PM
Physics Building, Room 204

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"Partial-Wave Analysis and Spectroscopy in Pion-Nucleon Scattering up to W = 2.5 GeV"


Igor I. Strakovsky , George Washington University
[Host: Donal Day]
ABSTRACT:
We present results from a comprehensive partial-wave analysis of pi+-p elastic scattering and charge-exchange data, covering the region from threshold to 2.6 GeV in the lab pion kinetic energy, employing a coupled-channel formalism to simultaneously fit pi-p-->eta n data to 0.8 GeV. Our main result, solution SP06, utilizes a complete set of forward and fixed-t dispersion relation constraints applied to the piN elastic amplitude. The results of these analyses are compared with previous solutions in terms of their resonance spectra and preferred values for couplings and low-energy parameters. Details are available at nucl-th/0605082
Nuclear
Tuesday, November 21, 2006
3:30 PM
Physics Building, Room 204

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"N/A"


Thanksgiving Recess , N/A
[Host: N/A]
ABSTRACT:
This talk will describe how to make intense identical positron and electron beams at Jefferson Lab and use them to measure two-photon exchange contributions to elastic electron-proton scattering. It will cover the results of a recent test run in CLAS where we produced about 10 pA each of electrons and positrons. The proton electric form factor describes the charge distribution of the proton. This has been measured extensively with electron scattering using Rosenbluth separations and polarization measurements. These measurements of the proton electric form factor disagree by a factor of three at Q 2 = 6 GeV 2 . Since alpha, the fine structure constant, is less than 1%, electron-proton scattering should be almost exclusively one-photon exchange. However, a two-photon exchange contribution of about 5% could explain the discrepancy between the measurements. We will determine the two-photon exchange contribution by measuring the ratio of the electron-proton and positron-proton elastic scattering cross sections to 1%.
Nuclear
Tuesday, October 10, 2006
3:30 PM
Physics Building, Room 204

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"A High Precision Measurement of G E n High Q 2 "


Brandon Craver , UVA
[Host: Donal Day]
ABSTRACT:
A precision measurement of the electric form factor of the neutron, G E n , has been carried out in Jefferson Lab's Hall A for Q 2 values of 1.2 to 3.5 (GeV/c) 2 using a highly polarized 3 He target and the quasi-elastic semi-exclusive 3 He(e,e'n) reaction. The experiment detected the ejected neutron with an array of scintillators and the scattered electron with the newly commissioned BigBite spectrometer. This new spectrometer has a large angular acceptance (80 msr), complementing the existing 6 msr high-resolution spectrometers, and enables a new generation of low-rate experiments with lower resolution requirements. A package of three multi-wire drift chambers was constructed in order to allow the spectrometer to operate under high rate conditions and achieve a spatial resolution of ~ 200 μm. The present status of the experiment will be presented as well as online results showing chamber performance at raw hit rates up to 20 MHz per plane.
Nuclear
Tuesday, September 26, 2006
3:30 PM
Physics Building, Room 204

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ABSTRACT:
I will make short introduction to clarify some notations used in N * physics and to present resonances which we have investigated within N * program of Hall B (JLab). Then I will discuss goals of N * program related to the Q 2 evolution of &gamma * N &rarr N * amplitudes. Here the focus will be on the investigation of the scale of transition from nonperturbative to perturbative regime of QCD and on the nature of the Roper resonance. Further, I will discuss approaches used for the extraction of resonance contributions to the pion electroproduction and present the results obtained from JLab (mostly Hall B) data. This will be followed by the discussion of the obtained results and conclusion.
See Special Colloquium
Tuesday, April 25, 2006
3:30 PM
Physics Building, Room 204

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"TBA"


RESERVED , TBA
[Host: Nilanga Liyanage]
Nuclear
Tuesday, April 18, 2006
3:30 PM
Physics Building, Room 204

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"Search for CP Violation in Hyperon Decays"


Chad Materniak , UVA
[Host: Donal Day]
Nuclear
Tuesday, April 11, 2006
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, April 4, 2006
3:30 PM
Physics Building, Room 204

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"Search for a Permanent Electric Dipole Moment (EDM) of the Neutron"


Dipangkar Dutta , Duke University
[Host: Donal Day]
ABSTRACT:
The search for a non-zero neutron EDM is a direct search for time reversal symmetry violation. Recently, a new experiment has been proposed to search for the neutron electric dipole moment (nEDM) with about two orders of magnitude improved sensitivity compared to the current experimental limit. One of the critical new ideas, which helps achieve the improved sensitivity, is the use of polarized Helium-3 as a co-magnetometer. Polarized He-3 is a key new component of this proposed experiment and thus maintaining its polarization under the true experimental conditions is essential for the success of the experiment. Following an overview of the past searches for the neutron EDM, I will describe the new experiment and the effort underway at Duke to study the relaxation of polarized He-3 under the conditions of the new proposed experiment.
Nuclear
Tuesday, March 21, 2006
3:30 PM
Physics Building, Room 204

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"Nucleon Spin Physics Program in JLab's Hall C"


Oscar Rondon-Aramayo , UVA
[Host: Donal Day]
ABSTRACT:
The Hall C facility at Jefferson Lab is carrying out an extensive program of studies on nucleon spin physics, taking advantage of the CEBAF polarized electron beam and the versatile UVa polarized target. The program started in 2002 with a measurement of the longitudinal and transverse spin structure of the nucleon resonances in experiment 01-006 (Resonances Spin Structure - RSS) on proton and deuteron targets. This work is nearing publication of the final results for the proton, which will be presented. Preliminary results for the deuteron are available, too. The Spin Asymmetries on the Nucleon Experiment - SANE (E-03-109) is in preparation to extend the measurements of RSS and other experiments on the proton to higher momentum transfers. Going beyond inclusive polarized scattering, the Semi-SANE experiment (E-04-113) will detect scattered electrons and hadrons in coincidence, to determine the decomposition of the nucleon spin into its quark flavor components. Both SANE and Semi-SANE are scheduled to take data in 2008."
Joint Nuclear/High Energy Physics Seminar
Monday, March 13, 2006
3:30 PM
Physics Building, Room 204

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"High Energy Limit and Parton Saturation in QCD"


Anna Stasto , Brookhaven National Laboratory
[Host: Peter Arnold]
ABSTRACT:
High energy limit of QCD is the area of major theoretical interest. One of its prediction is the so called perturbative BFKL Pomeron which manifests itself as a rapid growth of the gluon density with increasing center-of-mass energy. Although the rise of this density is indeed observed in the deep inelastic experiments at small values of Bjorken x, it is not compatible quantitatively with the prediction of the BFKL Pomeron. This lead to the intensive investigation of the possible corrections to the BFKL Pomeron such as higher order and the high density corrections. In this talk I will give an introduction to the high energy limit of QCD and discuss the idea of the parton saturation, an effect that is expected to occur when the gluon density is very high. I will describe the nonlinear evolution equation (Balitsky-Kovchegov equation) for the gluon density which takes into account high density corrections and present its solution. The concept of the saturation scale and the geometrical scaling at small Bjorken x will be also introduced as well as the interesting link between parton saturation in QCD and the statistical physics. Finally, I discuss some phenomenological signatures of parton saturation and outline recent theoretical progress in developing theory with so-called Pomeron loops, corrections which go beyond the Balitsky-Kovchegov equation.
Nuclear
Tuesday, March 7, 2006
3:30 PM
Physics Building, Room 204

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****SPRING RECESS****
Join Nuclear/High Energy Seminar
Tuesday, February 28, 2006
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, December 6, 2005
3:30 PM
Physics Building, Room 204

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"Partial-Wave Analysis of Scattering Reactions"


Richard Arndt , Virginia Tech
[Host: Donal Day]
Nuclear
Tuesday, November 29, 2005
3:30 PM
Physics Building, Room 204

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"Studying the QCD Equation of State with Hydrodynamics"


Pasi Huovinen , UVa and University of Jyväskylä, Finland
[Host: Donal Day]
ABSTRACT:
The lattice QCD calculations predict a phase transition from hadronic matter to matter where the basic degrees of freedom are partons instead of hadrons around 170 MeV temperature. It is hoped that this phase transition could be experimentally observed in the heavy ion collision experiments at BNL's RHIC collider. In this talk I will discuss how one can compare the lattice QCD predictions to experimental results by using hydrodynamics to describe the expansion stage of the collision process. The data favor a scenario with a phase transition, but surprisingly the order of the phase transition seems to be different from the QCD prediction.
Nuclear
Tuesday, November 22, 2005
3:30 PM
Physics Building, Room 204

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****THANKSGIVING BREAK****
This is a joint High Energy/Nuclear Seminar
Tuesday, November 8, 2005
3:30 PM
Physics Building, Room 204

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"Mixing Color and Spin"


John Ralston , University of Kansas
[Host: Simonetta Liuti]
Nuclear
Tuesday, November 1, 2005
3:30 PM
Physics Building, Room 204

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"Hunting the Pentaquark"


Stepan Stepanyan , Jefferson Lab
[Host: Donal Day]
ABSTRACT:
In the past two years more than 13 experiments have reported observation of a narrow exotic S=+1 baryon state in the mass range from 1.525 to 1.55 GeV/c2. The minimal quark content of this state, now called the Θ+, is uudds. In contrast to almost fully exclusive experiments at low energies that have reported evidence for the Θ+, there have been a number of reports of non-observation of this state, mostly in high energy inclusive experiments. The main criticisms of the reported Θ+ signals are insufficient statistics, and variation in mass. Evidence for the doubly strange, Φ-- (known as Ξ--),and for the charmed, Θc, pentaquarks have been presented only in the single experiments. The CLAS Collaboration at Jefferson Laboratory has published two papers on the experimental evidence for the Θ+ and Ξ--. These data now represent the world's largest data sets for photoproduction on hydrogen and deuterium. In this talk an overview of the experimental situation on the pentaquarks and the preliminary results of high statistics CLAS experiments will be presented.
Nuclear
Tuesday, October 25, 2005
3:30 PM
Physics Building, Room 204

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"Search for Gluonic Excitations at Jefferson Lab"


Elton Smith , Jefferson Lab
[Host: Donal Day]
ABSTRACT:
One of the great mysteries of modern physics is the mechanism that confines quarks into hadrons. Quarks are bound together due to the strong interaction of gluons which themselves carry color charge. Although the theory of quantum chromodynamics (QCD) describes the interaction, the solutions can only be approximated at low energies. Nevertheless colored gluons are expected to bind to each other and form flux tubes, which lattice QCD predicts will be observable in the particle spectrum as new excitations called hybrid mesons. We will describe the plans at Jefferson Lab to double the energy of the machine to 12 GeV, which will allow access these gluonic excitations experimentally, and describe the apparatus in the new Hall D which will be used to search for them.
Joint Nuclear/High Energy Seminar
Thursday, October 20, 2005
3:30 PM
Physics Building, Room 205

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"Transversity Properties of Quarks and Hadrons Through Hard Scattering in QCD"


Leonard Gamberg , Penn State
[Host: Simonetta Liuti]
Nuclear
Tuesday, October 4, 2005
3:30 PM
Physics Building, Room 204

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ABSTRACT:
The fleeting existence of quark-antiquark pairs within the proton (or neutron) is a well-established consequence of quantum chromodyamics. It is, however, still a largely open question as to whether this sea of quark-antiquark pairs, which contains contributions from all the quark flavors (up, down, strange, etc.), has any effect on the properties of the nucleon. In particular, the contribution of the sea to the magnetic moment and the charge distribution of the proton has been a topic of considerable interest. A series of experiments, using parity-violating electron scattering to probe of the sea, have been conducted at various labs in recent years. The results of these experiments, in particular the G0 and HAPPEX experiments at Jefferson Lab, will be reviewed, and possible interpretations of the results will be presented.
Nuclear
Tuesday, September 27, 2005
3:30 PM
Physics Building, Room 204

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"Higher-Order QED for Precision Studies of Electron Scattering"


Andrei Afanasev , Jefferson Lab
[Host: Donal Day]
ABSTRACT:
High precision of electron scattering experiments on nucleons and nuclei requires precise methods to include electromagnetic radiative corrections. Using an example of elastic electron-nucleon scattering, I will describe an important role of higher-order Quantum Electrodynamic techniques for the studies of hadronic structure with electron beams.
Nuclear
Tuesday, September 20, 2005
3:30 PM
Physics Building, Room 204

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"The BoNuS Experiment at Jefferson Lab"


Stephen Bueltmann , Old Dominion University
[Host: Donal Day]
ABSTRACT:
Unlike the structure of the proton, our understanding of the structure of the neutron to date is limited by the unavailability of free neutrons. The BoNuS collaboration at Jefferson Lab is preparing an experiment to augement the CLAS detector in Hall B with a recoil detector to measure the momentum of recoiling protons in electron scattering on a deuterium target. The detection of very low momentum spectator protons at very backward scattering angles selects electron scattering events on almost free neutrons inside the deuteron. The newly developed recoil detector and gas target system has to be built out of lightweight materials to not absorb the very low momentum spectator protons before being detected. The experiment is scheduled to start data taking in the middle of Octber 2005 and results from an engineering run in June 2005 are presented.
Nuclear
Tuesday, August 30, 2005
3:30 PM
Physics Building, Room 204

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AVAILABLE
Nuclear
Tuesday, April 26, 2005
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, April 19, 2005
3:30 PM
Physics Building, Room 204

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"Measurements of the Extended GDH Sum Rule at J-Lab"


Josh Pierce , UVA
[Host: Don Crabb]
Hoxton Lecture


Tuesday, April 19, 2005
7:30 PM
Chemistry Building Auditorium, Room 402

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"Supernovae, Dark Energy, and the Accelerating Universe"


Saul Perlmutter , University of California - Berkeley
[Host: Brad Cox]
ABSTRACT:

This constant acted as a sort of anti-gravity to counteract the force of gravity that would otherwise be pulling the masses of the universe together. When astronomers such as Hubble and others subsequently observed the red shifts of far distant stars and galaxies, they discovered that the universe is not static but, indeed, is expanding. Therefore, it no longer seemed necessary to have a counter balance to gravity. It is said that Einstein, when he heard of the expansion of the universe, characterized his use of a cosmological constant his greatest mistake. Indeed, for the better part of 100 years the standard view of the universe was that its expansion rate was gradually slowing down under the influence of the gravity of its components. The question of the future of the universe was posed in terms of, depending on the total mass of the universe, whether the universe would come to a stop and fall back in on itself, come to a halt at infinite time, or continue to expand forever. Professor Perlmutter and his colleagues, using Supernovas Type Ia as “standard candles” because of their great brightness, have measured the expansion rate of the universe at much large distances than previously possible. In doing so, they have made the remarkable discovery that the expansion of the universe is actually accelerating. There appears to be a previously undetected force of nature that acts like antigravity, dominating the gravitational force and causing the universe to expand faster and faster with time. So the better part of a century after the cosmological constant was abandoned, it seems that it must be re-employed to describe this new phenomenon which has been labeled dark energy. Perhaps Einstein was right after all!

Nuclear
Tuesday, April 12, 2005
3:30 PM
Physics Building, Room 204

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"Study of Bound Nucleons Using Generalized Parton Distributions"


Swadhin Taneja , UVA
[Host: Gordon Cates]
Nuclear
Tuesday, April 5, 2005
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, March 29, 2005
3:30 PM
Physics Building, Room 204

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"HAPPEX: Using Parity Violation to Probe Nucleon Strangeness"


Ryan Snyder , UVA
[Host: Gordon Cates]
Nuclear
Tuesday, November 30, 2004
3:30 PM
Physics Building, Room 204

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"Spin Structure Functions: A Window into the Structure of Hadrons"


Gail Dodge , Old Dominion University
[Host: Simonetta Liuti]
Nuclear
Tuesday, November 9, 2004
3:30 PM
, Room 204

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Nuclear
Wednesday, June 23, 2004
3:30 PM
Physics Building, Room 204

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"Measurements of the Electric Form Factor of the Neutron"


Shigeyuki Tajima , Duke University
[Host: Donal Day]
ABSTRACT:
Precise measurements of the electric form factor of the neutron, Gen, over a wide range of the square of the four-momentum transfer, Q^2, are important for understanding nucleon and nuclear electromagnetic structure. The Jefferson Laboratory E93-038 collaboration recently reported the first measurements of Gen using polarization techniques at Q^2 > 1 (GeV/c)^2. The collaboration measured the ratio of the electric form factor to magnetic form factors of the neutron, g = Gen/Gmn, at three Q^2 values (0.45, 1.13 and 1.45 (GeV/c)^2) using the quasi-elastic 2H(vec e,e'vec n)1H reaction. The value for g was determined from the measured ratio of the sideways and longitudinal components of the neutron polarization vector. A polarimeter based on np scattering was used to analyze the polarization of the recoil neutrons. In this talk, the data analyses and our results for g and Gen at Q^2=0.45 and 1.13 (GeV/c)^2 will be given.
Nuclear
Tuesday, April 27, 2004
3:30 PM
Physics Building, Room 204

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"Novel Transversity Properties in Semi-Inclusive Deep Inelastic Scattering"


Karapet Oganessyan , DESY
[Host: Simonetta Liuti]
Nuclear
Tuesday, April 20, 2004
2:00 PM
Physics Building, Room 313

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"The Proton Form Factor and the Shape of the Proton"


Gerald Miller , University of Washington
[Host: Simonetta Liuti]
Nuclear
Tuesday, April 20, 2004
3:30 PM
Physics Building, Room 204

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"Spin relazation of 129Xe from paramagnetic impurities"


Scott Rohrbaugh ( Biological Physics) , UVA
[Host: Gordon Cates]
Nuclear
Tuesday, March 30, 2004
3:30 PM
Physics Building, Room 204

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"Transverse Target Asymmetry in Exclusive Pi+ Production"


Dave Gaskell , Jefferson Laboratory
[Host: Donal Day]
Nuclear
Tuesday, March 2, 2004
3:30 PM
Physics Building, Room 204

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"Subatomic Journal Club"


Simonetta Liuti , UVA
[Host: Gordan Cates]
Nuclear
Tuesday, February 24, 2004
3:30 PM
Physics Building, Room 204

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ABSTRACT:
Studying few-body nuclear targets in the (e,e'p) reaction is a powerful method to investigate specific aspects of the nucleus. The 4He nucleus is an especially interesting target since it has many of the ingredients of a complex, heavy nucleus, while as an A=4 system, microscopic calculations are still feasible. Making use of the high luminosity electron beam at Jefferson Lab together with the high resolution spectrometers in Hall A, Jefferson Lab Hall A experiment E97-111 has measured the 4He(e,e'p)3He cross section at recoil momenta up to~500 MeV/c in various kinematics. In plane-wave impulse approximation, many calculations predict a sharp minimum in the cross section for recoil momenta around 450~MeV/c and show that its location is sensitive to the short-range part of the internucleon potential. However, reaction dynamic effects such as final-state interactions and meson-exchange currents can obscure such a minimum. Measuring this cross section at various kinematical settings over the same recoil-momentum range gives the possibility to study these reaction dynamics effects. Preliminary results of this experiment will be presented, and will be compared to recent theoretical predictions.
Nuclear
Tuesday, February 3, 2004
3:30 PM
Physics Building, Room 204

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"The latest global analyses of parton distribution functions"


Sergey Alekhin , Institute for HEP, Serpukhov
[Host: Simonetta Liuti]
Nuclear Seminar - PLEASE NOTE SPECIAL ROOM
Tuesday, December 9, 2003
3:30 PM
Physics Building, Room 313

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"Neutron Spin Structure at Low Q2 Using a Polarized 3He Target"


Karl Slifer , Temple University
[Host: Donal Day]
ABSTRACT:
We have measured the spin dependent longitudinal and transverse 3He(e,e,) cross sections for 0.12<0.9 GeV2 covering the quasielastic and resonance regions and extending into the deep inelastic scattering region. Jefferson Lab's longitudinally polarized electron beam of incident energy 0.8 GeV to 5.0 GeV was scattered from a high pressure polarized 3He target in experimental Hall A. Longitudinal and transverse target polarization was maintained, allowing extraction of both spin structure functions g1 and g2. This measurement allows evaluation of the structure function higher moments, including the extended GDH sum, for both 3He and the neutron. These results when compared to theoretical models provide insight into the transition from the perturbative to the non-perturbative regine of QCD.
Nuclear
Tuesday, November 11, 2003
3:30 PM
Physics Building, Room 204

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ABSTRACT:
This talk presents results of experiment E94-010 performed at JLAB (simply known as JLab) in Hall A. The experiment aimed to measure the low Q2 evolution of the Gerasimov-Drell-Hearn(GDH) integral from Q2 = 0.1 to 0.9 GeV2. The GDH sum rule at the real photon point provides an important test of Quantum Chromodynamics (QCD) radiative rections. The low Q2 evolutions of the GDH integral contests various resonance models. Chiral Perturbation Theory and lattice QCD calculations, but more importantly, it helps us understand the transition between partonic and hadronic degrees of freedom. At high Q2, beyond 1 GeV2, the difference of the GDH integrals for the proton and the neutron is related to the Bjorken sum rule, another fundamental test of QCD radiative corrections. In addition, results of the measurements for the spin structure functions g1 and g2 cross sections, and asymmetries are presented. E94-010 was the first experiment of its kind at JLAB. It used a high-pressure, polarized 3He target with a gas pressure of 10 atm and average target polarization of 38%. For the first time, the polarized electron source delivered an average beam plarization of 70% with a beam current of 15 µa; The limit on the beam current was only imposed by the target. The experiment required six different beam energies from 0.86 to 5.1 GeV. This was the first time the accelerator ever reached 5.1 GeV. Both High-Resolution Spectrometers of Hall A, used in singles mode, were positioned at 15.5 degree; each.
Nuclear
Tuesday, September 30, 2003
3:30 PM
Physics Building, Room 204

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"P+PBAR -> LAMBDA+LAMBDABAR WITH A POLARIZED TARGET"


Paul Kingsberry , Department of Physics and Astronomy, University of New Mexico
[Host: Donal Day]
ABSTRACT:
The reaction p+pbar -> lambda+lambdabar was examined by CERN experiment PS185/3 at the Low-Energy Antiproton Ring (LEAR) with beam momenta of 1.525 GeV/c and 1.640 GeV/c. The proton target was transversely polarized to enable measurements of the depolarization and spin transfer, which quantify the transfer of the transverse spin of the target proton to that of the outgoing lambda and lambdabar, respectively. Theoretical calculations of Dnn, the component of the depolarization normal to the production plane, differ greatly according to whether quark-gluon or meson-exchange models are utilized. Final results for the measured depolarization Dnn and spin transfer Knn will be presented for both beam momenta. These results appear to be inconsistent with the specific angular distributions predicted under the assumptions of both production scenarios.
Nuclear
Tuesday, May 20, 2003
3:30 PM
Physics Building, Room 313

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"Hadronization in Nucleus by Deep Inelastic Scattering"


Kebin Wang , UVA
[Host: Blaine Norum]
Nuclear
Tuesday, May 13, 2003
3:30 PM
Physics Building, Room 313

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"Development of CT-SPECT scanner for small animal imaging"


Alexander Stolin , UVA
[Host: Mark Williams]
Nuclear
Tuesday, May 6, 2003
3:30 PM
Physics Building, Room 313

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Nuclear
Tuesday, April 29, 2003
3:30 PM
Physics Building, Room 204

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"Achieving Proposed Accuracy in the PIBETA Experiment -- It's About Time!"


Brent A. VanDevender , UVA
[Host: Dinko Pocanic]
ABSTRACT:
In order for PIBETA to attain its proposed accuracy it is imperative that all electronic artifacts be removed from the timing scheme in offline analysis. Some progress has been made but it is evident that attepts to extend these improvements with traditional ADC/TDC methods will be impossible. The efforts can be salvaged however by studying digitized waveforms and developing new timing algorithms which exploit the raw signals.
Nuclear
Tuesday, April 22, 2003
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, April 15, 2003
3:30 PM
Physics Building, Room 204

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"PIBETA experiment: overview and preliminary results"


Maxim Bychkov , UVA
[Host: Dinko Pocanic]
Nuclear
Tuesday, March 11, 2003
3:30 PM
Physics Building, Room 204

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"The Unexpected Effects of Final-State Interactions in QCD"


Prof. Stanly J. Brodsky , SLAC
[Host: Xiaotong Song]
ABSTRACT:
It is usually assumed that the structure functions measured in deep inelastic lepton-proton scattering are the probability distributions for finding quarks and gluons in the target nucleon. In fact, gluon exchange between the fast, outgoing partons and the target spectators, which is usually assumed to be an irrelevant gauge artifact, affects the leading-twist structure functions in a profound way, leading to diffractive leptoproduction processes, shadowing of nuclear structure functions, and target spin asymmetries. In particular, final-state interactions from gluon exchange leads to single-spin asymmetries in semi-inclusive deep inelastic lepton-proton scattering which are not power-law suppressed at large photon virtuality Q^2 at fixed x_{bj}.
Nuclear
Tuesday, February 25, 2003
3:30 PM
Physics Building, Room 204

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"Study of the Porized Structure Functions of the Neutron at Low Q2 with Polarized 3He "


Dr. Senho Choi , Temple University
[Host: Nilanga Liyanage]
Nuclear
Tuesday, February 18, 2003
3:30 PM
Physics Building, Room 204

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"Spin and Statistics in Nonrelativistic Quantum Mechanics''"


Prof. Murray Peshkin , Argonne National Laboratory
[Host: Xiaotong]
ABSTRACT:
The connection between spin and statistics is usually proved by using the full machinery of relativistic quantum field theory, providing little insight into what physics actually underlies it or whether there can be exceptional cases. I will show, using elementary methods of ordinary nonrelativistic quantum mechanics that identical zero-spin particles must obey symmetric statistics. The key assumption is that no dynamical variable in the theory distinguishes among identical spin-zero particles. Whether this approach can be extended to identical particles with nonvanishing spin is currently uncertain.
Nuclear
Tuesday, January 14, 2003
3:30 PM
Physics Building, Room 204

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"Quark-Hadron Duality Studies in Polarised Structure Functions"


Alexandra Fantoni , INFN, Laboratorio Nazionale di Frascati
[Host: Simonetti Liuti]
SPECIAL NUCLEAR SEMINAR
Monday, November 25, 2002
3:30 PM
Physics Building, Room 204

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"'Peering deeply into the proton: Deeply Virtual Compton Scattering and Generalized Parton Distributions"


Charles Earl Hyde-Wright , Old Dominion University
[Host: Donal Day]
Special Nuclear Seminar
Tuesday, October 22, 2002
3:30 PM
Physics Building, Room 204

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"Radiation and Gravity"


Mike Clark , NRPB - England
[Host: George Gillies]
ABSTRACT:
The standard phenomenological model for the interaction for ionising radiation with matter, originally formulated by Bethe and widely used to calculate the transfer of energy, can also be used to model the quantum exchange processes that mediate forces. Such models are shown to be compatible with Newtonian gravitation and with the principle of weak equivalence. The gravitational constant G (kg –1 m3 s –2) can be related to Planck’s constant h, the speed of light c, the atomic mass unit u, and a dimensionless coupling constant ag. The applications and implications of the derived formulation will be examined. This formulation for G gives a new interpretation of Planck quantities, and a prediction emerges for experimental values of G to increase with increasing temperature of the attracting mass. Finally, gravitational shielding is predicted to occur but at vanishingly small proportions both in the laboratory and in the cosmos. * M J Clark is at the National Radiological Protection Board, Chilton, Didcot, OX11 0RQ, UK (e-mail mike.clark@nrpb.org.uk).
Nuclear
Tuesday, April 30, 2002
3:30 PM
Physics Building, Room 204

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"Measurement of the Ratio G_Ep/G_Mp at large Q^2 at Jefferson Lab"


Vina Punjabi , Norfolk State University
[Host: S. Liuti]
Nuclear
Tuesday, February 26, 2002
3:30 PM
Physics Building, Room 204

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"Generalized parton distributions and their ramifications"


Markus Diehl , DESY
[Host: G. Cates]
Nuclear
Tuesday, January 15, 2002
3:30 PM
Physics Building, Room 204

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" Quark-Gluon-Plasma Theory: Overview of status and perspectives"


Stefen Bass , Department of Physics, Duke University & RIKEN-BNL Research Center Fellow
[Host: S. Liuti]
ABSTRACT:
It is believed that shortly after the creation of the universe in the Big Bang all matter was in a state called the Quark Gluon Plasma (QGP). Due to the rapid expansion of the Universe, this plasma went through a phase transition to form hadrons and nuclear matter as we know it today. The investigation of QGP properties will yield important novel insights into the development of the early universe and the behavior of QCD under extreme conditions. It is sought to recreate this highly excited state of primordial matter under controlled laboratory conditions using relativistic heavy ion collisions, e.g. at the Super-Proton-Synchrotron (SPS) at CERN and at the Relativistic Heavy-Ion Collider (RHIC) at Brookhaven National Laboratory. SPS and first RHIC data have yielded many interesting and sometimes surprising results which have not yet been fully evaluated or understood by theory. I will review the current status of QGP theory - main emphasis will be put on what we have learned at the SPS and at RHIC and what the most pressing challenges are for the near future.
Nuclear
Tuesday, December 4, 2001
3:30 PM
Physics Building, Room 204

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"Nuclear Physics of Parton Distributions"


Sergey Kulagin , Institute for Nuclear REsearch, Moscow
[Host: S. Liuti]
Nuclear
Tuesday, November 13, 2001
3:30 PM
Physics Building, Room 204

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"GDH Sum Rule"


X. Ji , University of Maryland
[Host: Xiatong Song]
Nuclear
Tuesday, October 23, 2001
3:30 PM
Physics Building, Room 204

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ABSTRACT:
Inclusive double spin asymmetries p(e,e') measured in Hall-B at Jefferson Lab show that the resonance region contributes significantly to the low Q2 (0.15-1.2 GeV2) evolution of the structure function gp1(x,Q2) and its first moment. These results have important implications for the limits of current pQCD predictions as well as for the expected low Q2 convergence to the Gerasimov-Drell-Hearn Sum Rule.
Nuclear
Tuesday, October 9, 2001
3:30 PM
Physics Building, Room 204

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"A Random Walk in the Physics of Light Nuclei"


Rocco Schiavilla , JLAB
[Host: H. J. Weber]
ABSTRACT:
In this talk I will discuss our current understanding, based on realistic nuclear Hamiltonians and currents, of a number of disparate issues generally relating to the structure and dynamics of light nuclei. These include: energy spectra of light nuclei with A up to 10, the determination of GEn from d(e,e')d data, longitudinal and transverse strength in the quasi-elastic (e,e') response of nuclei, the determination of parity-violating components of the NN interaction from pp elastic scattering, and finally (time permitting) an update on hep neutrinos from SuperK.
Please Note Special Date and Time
Thursday, September 27, 2001
3:30 PM
Physics Building, Room 204

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"Polarized Scintillating Targets for Spin Physics"


Patrick Hautle , PSI
[Host: Donald Crabb]
Nuclear
Tuesday, September 25, 2001
3:30 PM
Physics Building, Room 204

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"Chiral Dynamics of the eta-prime meson"


B. Borosoy , Technical University
[Host: Blaine Norum]
ABSTRACT:
The lowest-lying nonet of pseudoscalar mesons consists of the Goldstone boson octet of pions, kaons and the eta, which become massless in the chiral limit of zero quark masses, and the corresponding singlet state, the eta-prime, which, on the other hand, remains a massive state in the chiral limit due to the axial U(1) anomaly. In order to describe the interactions of the eta-prime with the Goldstone boson octet at low energies, the conventional chiral effective Lagrangian is extended to include the eta-prime. The results presented in this talk include (eta)-(eta-prime) mixing and the dominant decay mode of the eta-prime into (eta bion pion). Furthermore, we conbine the chiral Lagrangian approach with a coupled channel analysis, in order to investigate eta-prime electroproduction off the nucleons. The investigation of the eta-prime may offer new insights into the role of the axial U(1) anomaly in chiral dynamics.
Nuclear
Tuesday, September 18, 2001
3:30 PM
Physics Building, Room 204

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Special Research Talk
Tuesday, May 1, 2001
4:00 PM
Physics Building, Room 204

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"Probing Quantum Phase Transitions with NanoCalorimeter"


Yongsoo Yoon , Univ. of California
[Host: Thomas Gallagher]
Nuclear
Tuesday, April 17, 2001
3:30 PM
Physics Building, Room 204

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"N N Corelations in 3He(e,e'pp) n' "


Larry Weinstein , ODU
[Host: Ralph Minehart]
Nuclear
Tuesday, April 10, 2001
3:30 PM
Physics Building, Room 204

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"Exploring Quark-Hadron Duality at Medium Energies"


Ioana Niculescu , Jefferson Lab
[Host: D. Pocanic]
ABSTRACT:
Quark-hadron duality reflects the relationship between the quark and hadron descriptions of hadronic processes and is related to the nature of the transition from non-perturbative to perturbative QCD. The phenomenon of duality can be studied in a variety of processes, such as e+e- annihilation, deep inelastic scattering, heavy quark decays, etc. Recent data on inclusive electron-proton and electron-deuteron inelastic scattering obtained at Jefferson Lab were utilized for precision tests of quark-hadron duality. These results will be presented, together with future plans of testing/expanding the concept of quark-hadron duality at Jefferson Lab.
Nuclear
Tuesday, April 3, 2001
3:30 PM
Physics Building, Room 204

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"Probing the Spin Structure of Strangeness Production: "


Kent Pashke , Carnegie Mellon
[Host: Ralph Minehart]
Special Colloquium
Tuesday, March 20, 2001
3:30 PM
Physics Building, Room 204

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"The Chiral Anomaly and Neutral Pion Lifetime"


Ashot Gasparian , Jefferson Lab
[Host: Gordon Cates]
ABSTRACT:
The system of the three light neutral mesons, pi-zero, eta eta-prime, contains fundamental information about chiral symmetry breaking in low energy QCD. In particular, SU(3)and isospin breaking by the light quark masses lead to important mixing effects among the mesons. Because of the small mass of the pion, the prediction of the chiral anomaly for the pi-zero To gamma - gamma decay width is more accurate and exact in the limit of massless quarks. In this limit the predicted decay width depends only on two fundamental constants: the number of colors in QCD,and the pion decay constant.The “PrimEx ” collaboration at Jefferson Lab will perform a high precision measurement of the neutral pion lifetime using the small angle coherent photoproduction of pi-zero's in the Coulomb field of a nucleus,i.e., the Primakoff effect. After giving a general overview of chiral symmetry breaking and the appearance of the chiral anomaly at low energies,this talk will present previous measurements and focus on the current experiment at JLab. The experimental program for the more massive eta and eta-prime mesons with the 12 GeV JLab energy upgrade will also be discussed.
Nuclear
Tuesday, February 13, 2001
3:30 PM
Physics Building, Room 204

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"The measurement of the spin structure function g1 in the resonance region"


Yelena Prok , University of Virginia - Physics Dept.
[Host: Dinko Pocanic]
Nuclear
Tuesday, December 12, 2000
3:30 PM
Physics Building, Room 204

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"TBA"


Raju Venugopalan (POSTPONED) , BNL
[Host: Simonetta Liuti]
Nuclear
Tuesday, December 5, 2000
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, November 21, 2000
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, October 24, 2000
3:30 PM
Physics Building, Room 204

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"TBA"


Gordon Cates (POSTPONED) , UVA- Physics Department
Nuclear
Tuesday, October 17, 2000
3:30 PM
Physics Building, Room 204

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Nuclear
Tuesday, October 10, 2000
3:30 PM
Physics Building, Room 204

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"Is There A Tensor Admixture To V-A Interaction In The Radiative Pion Decay?"


Emil Frlez , University of Virginia
[Host: Dinko Pocanic]
ABSTRACT:
The PIBETA experiment at PSI has been taking data for over a year. Acquired statistics of rare pion and muon decays exceeds now the previous world total by up to an order of magnitude. In this talk I will examine the pi+ --> e+ gamma events collected so far, especially in the part of the phase space sensitive to deviations from the canonical V-A interaction. As the PIBETA detector is running with 12 simultaneous physics triggers, the cross-normalization of different decay channels enables us to extract the absolute pi+ --> e+ nu gamma branching ratio in a simple way and compare it with a straightforward theoretical calculation.
Special Instrumentation Seminar
Tuesday, October 3, 2000
3:30 PM
Physics Building, Room 204

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"Waveform Digitization with the Domino Sampling Chip in the PIBETA Experiment"


H. P. Wirtz , Paul Scherrer Institute
[Host: D. Pocanic]
*Nuclear Seminar- Please note change in room location
Monday, September 25, 2000
3:30 PM
Physics Building, Room 313

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"Many Body Theory Interpretation of Deep Inelastic Scattering"


I. Sick , Univ. Basel
[Host: Donal Day]
National Physics Day Show
Thursday, April 27, 2000
6:30 PM
Physics Building, Room 203

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"The Sixth Annual National Physics Day Show"


Stephen Thornton/Robert Watkins , University of Virginia
[Host: Physics Department]
SPECIAL CHEMICAL PHYSICS SEMINAR
Tuesday, April 18, 2000
3:30 PM
Physics Building, Room 204

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"Surface Dynamics Using Synchrotron Radiation"


Gwyn Williams , JLAB
[Host: Robert Jones]
Nuclear
Tuesday, April 11, 2000
3:30 PM
Physics Building, Room 204

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"A Search for Color van der Waals Interaction"


C V K Baba , Tata Institute of Fundamental Research, Bombay
[Host: P. K. Kabir]
Nuclear
Tuesday, April 4, 2000
3:30 PM
Physics Building, Room 204

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"Spin Structure Function g2"


Xiatong Song , University of Virginia
[Host: Hans J. Weber]
Joint Nuclear/High Energy
Tuesday, March 21, 2000
3:30 PM
Physics Building, Room 204

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"Search for the Origin of Duality"


Sabine Jeschonnek , Jefferson Lab
[Host: Simonetta Liuti]
Nuclear
Tuesday, March 14, 2000
3:30 PM
Physics Building, Room 204

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"Precision Measurement of the Spin Structure of the Proton and the Deuteron"


Frank Wesselmann , Old Dominion University
[Host: Donal Day]
ABSTRACT:
Over the past decade, many experiments have measured the nucleon spin structure functions using polarized deep inelastic scattering, both in the US and in Europe. After a brief survey of these efforts, the results from SLAC experiments E155 and E155x will be presented. This pair of experiments has measured g1 and g2 of the proton and the deuteron with high precision and over a large kinematic range, providing the best measurements available. In the discussion of these measurements, special attention will be given to the radiative corrections, which have a significant impact on the measured results and also on statistical and on systematic errors.
Nuclear
Tuesday, March 7, 2000
3:30 PM
Physics Building, Room 204

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"CEBAF @ Jefferson Lab: A New Microscope for Nuclear Physics"


Larry Cardman , Jefferson Laboratory, Newport News, VA
[Host: Blaine Norum]
Nuclear
Tuesday, February 29, 2000
3:30 PM
Physics Building, Room 204

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"A Precise Measurement of the g2 Structure Function of the Proton and Deuteron"


Dustin McNulty , University of Virginia
[Host: Don Crabb]
Special Nuclear Seminar
Thursday, January 27, 2000
3:00 PM
Physics Building, Room 313

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"Theoretical issues of interacting mesons, baryons and photons"


Helmut Haberzettl , George Washington University
[Host: Hans Weber]
*Special Science Education Seminar
Tuesday, December 14, 1999
3:30 PM
Physics Building, Room 203

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"Web-based Software to Enhance Instructor-Student Interaction"


Dr. William Junkin , Erskine College
[Host: Stephen Thornton]
ABSTRACT:
Web-based (HTML) software will be introduced which enhances student learning by increasing student involvement and instructor-student interaction. Most of these interactive or polling software and templates, some of which I have developed, are free. They are used in "Peer Instruction" developed by Eric Mazur (Harvard University) and "JiTT" (Just-in-Time Teaching) developed by Novak and Garvin (IUPUI), Patterson (Air Force Academy), and Christian (Davidson). These recent pedagogies have been used effectively in physics and other disciplines at the high school and undergraduate level. Preliminary results of using some of this software with traditional introductory physics labs are especially promising. This session will demonstrate these materials, make them available to those that are interested, explain how to make them work on your platform or network, explain how to combine them with other web-based materials, and mention results from using them. The session is designed for anyone, novice web-surfer to experienced web-master.
Nuclear
Tuesday, October 26, 1999
3:30 PM
Physics Building, Room 204

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"Mirror nuclei, the neutron and quark-hadron duality"


Wally Melintchouk , University of Aolelaisle/Jefferson Lab
[Host: S. Luiti]
Nuclear
Tuesday, October 19, 1999
3:30 PM
Physics Building, Room 204

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"Substructure of the Nucleon"


Xiaotong Song , University of Virginia - Physics Dept
Nuclear
Tuesday, October 5, 1999
3:30 PM
Physics Building, Room 204

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"Probing Chiral Symmetry with Photonuclear Reactions"


Norm Kolb , University of Saskachewan
[Host: Blaine Norum]
ABSTRACT:
Chiral Perturbation Theory (ChPT) is an effective field theory in which the spontaneous breaking of the Quantum Chromodynamic (QCD) chiral symmetry is exploited to make predictions for many low-energy processes. Nuclear Compton scattering and near-threshold pion photoproduction are two of the phenomena that can be used to test the chiral dynamics of QCD via ChPT. Compton scattering can be used to extract the electric and magnetic polarizabilites of the nucleon, which are fundamental structure constants. Pion photoproduction close to threshold determines the fundamental pion-nucleon amplitudes in a model-independent way. The proton polarizabilities and pion-proton threshold amplitude are in reasonable agreement with predictions. The situation for the neutron is not nearly so good, both on an experimental as well as theoretical basis. Experimental results from these programs at the Saskatchewan Accelerator Laboratory will be reviewed.
Nuclear
Tuesday, September 21, 1999
3:30 PM
Physics Building, Room 204

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"Topics in N* Resonance Analysis"


R. Workman , George Washington University
[Host: Hans Weber]

To add a speaker, send an email to dmk9m@Virginia.EDU Include the seminar type (e.g. Nuclear Physics Seminars), date, name of the speaker, title of talk, and an abstract (if available). [Please send a copy of the email to phys-speakers@Virginia.EDU.]