VU Physics and Astronomy Colloquium

Friday, October 31, 2008. Join us in NSC 231 at 3:05 for refreshments. Talk starts at 3:20 in NSC 224.

"Characterizing the Underlying Event in Proton-Proton Collisions"

Megan Kania, Nate Kellams, & Tim Olsen, VU Department of Physics & Astronomy

The STAR collaboration seeks to quantify the proportion of the intrinsic spin of a proton contributed by the collective spins of gluons within the nucleon. Measurements are made by analyzing the products of polarized proton-proton collisions. The most useful collisions for this study are those involving a quark-gluon collision which produce a particular photon and quark jet signal. However, due to the presence of other particles in the neighborhood of the collision (i.e. the other quarks and gluons in the collided protons) the photon and jet will be mixed with the particles from that underlying event. Quantitatively characterizing the underlying event enables us to correct the analysis to exclude those extraneous particles.