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DESCRIPTION:Bernd Surrow \, Temple University\n\nUnderstanding the structur
e of matter in terms of its underlying constituents has a long tradition i
n science. A key question is how we can understand the properties of the p
roton\, such as its mass\, charge\, and spin (intrinsic angular momentum)
in terms of its underlying constituents: nearly massless quarks (building
blocks) and massless gluons (force carriers). The strong force that confin
es quarks inside the proton leads to the creation of abundant gluons and q
uark-antiquark pairs (QCD sea). These ‘silent partners’ make the domin
ant contribution to the mass of the proton. Various polarized deep-inelast
ic scattering measurements have shown that the spins of all quarks and ant
iquarks combined account for only 25% of the proton spin. New experimental
techniques are required to deepen our understanding on the role of gluons
and the QCD sea to the proton spin. High energy polarized proton-proton (
p + p) collisions at RHIC at Brookhaven National Laboratory
provide a new and unique way to probe the proton spin structure using very
well established processes in high-energy physics\, both experimentally a
nd theoretically. A major new tool has been established for the first time
using parity-violating W boson production in polarized p + p collisions at ͩ
0\;s = 500 GeV d
emonstrating directly the different polarization patterns of different qua
rk flavors\, paving the path to study the polarization of the QCD sea. Var
ious results in polarized p + p collisions at √\;s = 200 GeV constrain the degree to which g
luons are polarized suggesting that the contribution of the gluons to the
spin of the proton is rather small\, in striking contrast to their role in
making up the mass of the proton.
DTSTART:20120406T200000Z
LOCATION:Physics Building\, Room 204
SUMMARY:Fundamental measurements of the proton's sub-structure using high-e
nergy polarized proton-proton collisions
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