VU Physics and Astronomy Colloquium

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.