Friday, January 21, at 3:20 PM in NSC 224. Join us for refreshments in NSC 231 at 3:05 PM.
"Exploring Gluon Structure with Quark Probes"
Dr. Greg Rakness, University of California, Los Angeles
Over the past several decades, a significant effort has been expended in high
energy and nuclear physics research to understand the fundamental structure
of the proton in terms of quarks and gluons. Standard techniques have been
developed to pin down this structure precisely, including the scattering of
electrons off of protons over a broad range of energies and angles. The
impressive achievements notwithstanding, the precision of the knowledge about
the proton is in contrast with that of heavy nuclei, of which very little is
known about the gluon structure. In this talk I explain these techniques, review the current status, and describe a different type
of experiment that is sensitive to gluon structure, one which uses quarks
to probe the gluons in heavy nuclei. First results indicate that the nuclear
gluon density is significantly smaller than expected, and exhibits dynamics
which may require a new description of dense gluon fields. These results
potentially have impact on the experimental explorations currently underway
in high energy physics, heavy ion physics, and cosmology.