Longitudinal double spin asymmetry in jet production at STAR

TL;DR

This paper reports measurements of the longitudinal double-spin asymmetry in jet production at STAR, providing new data to constrain the gluon contribution to the proton's spin using polarized proton collisions at 200 GeV.

Contribution

It presents expanded transverse momentum coverage of A_LL measurements in jet production, offering more precise constraints on gluon polarization within the proton.

Findings

A_LL measurements are consistent with perturbative QCD predictions.

Results provide sensitive constraints on the gluon spin contribution.

Expanded pT coverage improves understanding of proton spin structure.

Abstract

We present recent measurements of the longitudinal double-spin asymmetry A_LL for the inclusive production of jets at midrapidity in polarized proton-proton collisions at sqrt(s)=200GeV. The data amount to an integrated luminosity of 3pb-1 and were collected with the STAR detector at the Relativistic Heavy Ion Collider during the year 2005 with average beam polarizations of about 50%. The ALL measurements cover jet transverse momenta 5 < pT < 30 GeV/c expanding the pT coverage over previously published data. The results will be compared with perturbative QCD evaluations and shown to provide sensitive constraints on the gluon spin contribution to the nucleon spin.