Experimental HEP Seminar

Measuring the Gluon Polarizations of Protons with Jets at RHIC

David Staszak

UCLA

A primary objective of the RHIC Spin physics program is the determination of the polarized gluon distribution function, ΔG, in the nucleon. I'll discuss the most recent measurement of the longitudinal spin asymmetry A_LL in the inclusive jet channel, which is directly sensitive to ΔG. The inclusive jet channel has the advantages of a high production cross section and little sensitivity to fragmentation functions, so it provides a significant early look at ΔG. The data presented here come from polarized proton-proton collisions at center of mass energies of 200 GeV with typical beam polarizations of 55%. I will compare the measured A_LL values to predictions derived from various parameterizations of the polarized gluon distribution function. The results are shown to provide significant constraints for allowable gluon parameterizations within STAR's kinematic x range of 0.05<x<0.2.