Recent STAR Jet Results of the High-Energy Spin Physics Program at RHIC

Abstract

The production of jets from polarized proton+proton collisions at STAR is dominated by quark-gluon and gluon-gluon scattering. The dijet double spin asymmetry (A\tsub{LL}) is sensitive to the polarized gluon distribution ($\Delta g(x)$). Dijets are also advantageous because the parton momentum fraction, x, of initial partons may be reconstructed to first order from the final state measurements. Both jet and dijet A\tsub{LL} measurements at $\sqrt{s}$ = 200 GeV have helped to constrain $\Delta g(x)$ in the range $0.05 < x < 0.3$. In 2012, data were collected at $\sqrt{s}$ = 510 GeV in order to probe lower values of x, these data are consistent with the $\sqrt{s}$ = 200 GeV results in the overlapping $x_T$ region. Jet and dijet preliminary A\tsub{LL} results have been released and will soon be incorporated into global analyses. In 2013, high luminosity data, with an estimated 250 pb$^{-1}$ of integrated luminosity were collected at $\sqrt{s}$ = 510 GeV. These data have a figure of merit of $\sim$3 times that of the 2012 data. An update on the dijet A\tsub{LL} measurement will be presented using polarized p+p data collected at STAR during 2013.