Testing various polarized parton distributions at RHIC
J. Soffer, J. -M. Virey
TL;DR
The paper assesses how RHIC can discriminate among polarized parton distributions, with a focus on Delta G and flavor-separated quark/antiquark polarizations, by analyzing spin asymmetries in direct photon, jet, and W production. It surveys several PDF sets (BS95, BouBuc, GS96, GRSV) and derives expectations for A_LL and A_L across these processes, including error estimates for high-luminosity running. Direct photon and jet asymmetries offer sensitivity to gluon polarization, while W production enables clean flavor separation of quark and antiquark polarizations, with pn collisions providing additional access. The study underlines RHIC's potential to advance understanding of the QCD spin sector and to test interpretations of the Ellis-Jaffe sum rule violations via Delta G.
Abstract
A very promising spin physics programme will be soon on the way at the BNL Relativistic Heavy Ion Collider (RHIC). By studying the spin asymmetries for various processes (single photon, single-jet and $W^{\pm}$ production), we will compare the different predictions obtained using some sets of polarized parton distributions, available in the recent literature. We will put some emphasize on the analysis of the anticipated errors, given the event rates expected from this high luminosity new machine and the current acceptance for the detector systems at RHIC.