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 Physics at Virginia

"Gravitational-waves: from black holes to the cosmos"


Maximiliano Isi , Flatiron Institute
[Host: Sayantani Datta]
ABSTRACT:

With the LIGO-Virgo detectors currently undergoing their 4th observing round, gravitational-wave astronomy has matured into a fast-developing field with broad implications for astrophysics, nuclear physics, gravity and cosmology. In this talk, I will focus on recent developments in probing the physics of black holes and their mergers with gravitational waves. This includes measurements of black hole spins and merger kicks, their use as cosmological probes, and the spectroscopic study of ringing black holes. I will outline some of the theoretical and observational questions driving this field: how do black holes form? Can we leverage them as probes of new fundamental fields, dark matter or cosmic expansion? I will conclude by arguing that we are at the cusp of observationally tackling these and many other fascinating questions as we enter the era of precision gravitational-wave science, with current and future observatories in space and on the ground.

Gravity Seminar
Monday, March 25, 2024
1:30 PM
Physics, Room 323
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Available
Atomic Physics Seminar
Monday, March 25, 2024
3:30 PM
, Room TBA
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"TBA"


Reserved for HEP Seminar
Nuclear Physics Seminar
Tuesday, March 26, 2024
3:30 PM
, Room TBA
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"Current and Future Searches for New Physics at Fixed Target Experiments"


Tyler Horoho , University of Virginia
[Host: Craig Dukes]
ABSTRACT:

The Standard Model of particle physics is our most complete and accurate picture of the Universe, but there are many questions that it cannot answer: What is the particle identity of dark matter? Why was there so much more matter than antimatter in the early universe? How do neutrinos get their mass? Answers to these questions and more are within reach to current and next generation fixed target experiments at accelerator facilities. This talk will discuss a search for light dark matter with the NOvA experiment, an ongoing long-baseline neutrino experiment, and future searches for light dark matter with the Light Dark Matter eXperiment. Additionally, I will present ongoing efforts to measure the efficiency of the Cosmic Ray Veto for the Mu2e experiment, which will probe for charged lepton flavor violation with world-leading precision.

High Energy Physics Seminar
Tuesday, March 26, 2024
3:30 PM
Gibson Hall, Room 211
Note special date.
Note special room.

Zoom: https://virginia.zoom.us/j/4349825364?pwd=blBZQWFzQitUT2k1Q1lyaG85Nm84QT09

Meeting ID: 434 982 5364
Passcode: Mu2e


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"A 2nd detector for the EIC"


Pawel Nadel Turonski , Stony Brook University
[Host: Simonetta Liuti]
ABSTRACT:

The Electron-Ion Collider (EIC) is the next-generation US-based project for QCD and nuclear science. It will collide polarized electrons with polarized protons and light ions, as well as heavier ions across the full mass range, at a high luminosity, over a wide range of c.m. energies. The first detector (ePIC) will support a broad science program, but having two detectors would significantly expand the capabilities of the EIC. The possibility to cross check results between the two detectors will enhance the discovery potential, and as in the case of H1 and ZEUS, combining data could reduce the overall systematic uncertainties. The latter will be even more relevant for the EIC than it was for HERA since once the luminosity ramps up to its nominal value, most EIC measurements will be limited by systematics. And those that require the highest luminosities (e.g., exclusive reactions and femtography of nucleons and nuclei) would greatly benefit from an improved far-forward near-beam acceptance, which is the main feature of the interaction region (IR8) where the 2nd detector could be located. The ability to detect recoiling light nucleus in coherent processes down to pT = 0, as well as almost all nuclear fragments in reactions where the nucleus breaks up (which also can be used to veto breakup in medium and heavy nuclei) will enhance the nuclear part of the EIC program and making it the ideal tool for femtography in the region dominated by sea quarks and gluons. The 2nd detector will also provide complementary capabilities to ePIC in other areas (e.g., improved muon detection), and will benefit from the ongoing Generic EIC Detector R&D program. This seminar will give an introduction to the 2nd detector, with a particular focus on exclusive reactions, and discuss some of the unique opportunities that a 2nd detector could bring to the EIC.

Nuclear Physics Seminar
Tuesday, March 26, 2024
3:30 PM
Monroe Hall, Room 134
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"Searches for long-lived dark matter with the CMS detector"


Prof. Allie Hall , US Naval Academy
[Host: Chris Neu]
ABSTRACT:

The CMS and ATLAS experiments at the CERN LHC have the unique potential to observe and study dark matter that could be produced in proton-proton collisions. Many searches for dark matter have been carried out, mostly focused on Mono-X signatures with "missing" transverse momentum. These searches, however, have so far not observed any evidence for dark matter and are setting increasingly stringent limits on the allowed dark matter mass and cross section. In this talk, I will describe the current CMS dark matter search program, including searches for long-lived dark matter particles that travel some macroscopic distance before decaying within the CMS detector. In particular, I will present a recent CMS search for an inelastic dark matter model in a final state with a pair of collinear, displaced muons and missing transverse momentum and discuss future plans for searches, including for models of self-interacting dark matter.

High Energy Physics Seminar
Wednesday, March 27, 2024
4:00 PM
Dell 2, Room 100
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"Linear-in-temperature conductance in electron hydrodynamics"


Leonid Levitov , MIT
[Host: Dima Pesin]
ABSTRACT:

Linear temperature dependence of transport coefficients in metals is habitually ascribed to non-Fermi-liquid physics. In this talk we establish this behavior for 2D electron fluids, systems in which carrier collisions assist conduction, leading to resistance decreasing with temperature. As we will see, electron fluids with simple Fermi surfaces obey nonclassical hydrodynamics described by a loop representing the Fermi surface shape evolving in space and time. Replacing the fluid velocity dynamics with an amoeba-like loop dynamics leads to a large family of long-lived excitations manifest as multiple viscous modes. A cascade of these modes results in a linear T dependence that extends down to lowest temperatures, as well as a Kolmogorov-like fractional power -5/3 scaling of conductivity vs. wavenumber. These dependences provide a smoking gun for nonclassical hydrodynamics and are expected to be generic for strongly-correlated 2D systems with near-circular Fermi surfaces.

Condensed Matter Seminar
Thursday, March 28, 2024
2:00 PM
Monroe Hall, Room 118
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ABSTRACT:

A series of connected research projects has been carried out for the purpose of seeking physics phenomena beyond the Standard Model. These consist of a precise measurement of the lifetime of a short-lived b-hadron, the Bd-meson; preparations for measurements of CP-violating parameters in Bs decays; development of triggers that select b-hadron events; development of new instruments for improved precision in detecting fundamental particles; and monitoring and mitigating the effect of radiation on the detectors, which is inescapable in their operating environment. Datasets collected by the ATLAS detector at the Large Hadron Collider (LHC) are used for the analyses involving the decays of b-hadrons. These analyses are supplemented by a detailed study of the evolution of the radiation effects in the current and upgraded ATLAS Pixel Detectors, using a radiation damage model and improving the model with the data collected at high luminosities. In the end, a set of comprehensive quality control tests, which include electrical and mechanical tests, has been carried out on the modules of the ATLAS Upgrade Pixel Detector.

High Energy Physics Seminar
Thursday, March 28, 2024
3:30 PM
Zoom, Room linked below
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Note special room.

Zoom: https://urldefense.proofpoint.com/v2/url?u=https-3A__cern.zoom.us


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ABSTRACT:

Pairing PbS quantum dots (QDs) with photochromic molecules (PCMs) allows for the synthesis of efficient and reversible near infrared photoluminescence (PL) photo-switches. In our work, we explore the utility space of this hybrid system by systematically comparing and contrasting different types of PCMs and different sizes of QDs. We demonstrate that the amount of photo-switching observed can be affected by (1) varying the size of the QDs, (2) varying the length of the PCMs, (3) fluorinating the PCMs, (4) varying the end group of the PCMs. We further investigate this system to parse out the mechanisms which may be responsible for this behavior. We present strong evidence to suggest that the mechanism driving this switching effect is an inter-QD tunneling process. We demonstrate a possible link between the energy levels of the PCMs and the magnitude of the switching effect and outline a rough empirical model which can guide the future design of QD/PCM photo switches to produce customized switching properties.

Condensed Matter Seminar
Thursday, March 28, 2024
3:30 PM
Gibson Hall, Room 211
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Available
Colloquium
Friday, March 29, 2024
3:30 PM
, Room TBA
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Zoom Link:  https://web.phys.virginia.edu/Private/Covid-19/colloquium.asp


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To add a speaker, send an email to phys-speakers@Virginia.EDU. Please include the seminar type (e.g. Seminars and Colloquia), date, name of the speaker, title of talk, and an abstract (if available).