Using Longitudinally Polarized Proton+Proton Collisions To Constrain the Polarized Gluon Distribution Through Dijet Measurements at $\sqrt{s} = 510$ GeV at STAR

The production of jets from polarized p+p collisions at STAR is dominated by quark-gluon and gluon-gluon scattering. The dijet double spin asymmetry ($A_{LL}$) 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. New data from 2013 with an estimated 250 pb$^{-1}$, at a beam polarization of $\sim$55\% at $\sqrt{s}$ = 510 GeV, has a figure of merit $\sim$3 times that of the 2012 data collected at $\sqrt{s}$ = 510 GeV. This talk will discuss the new dijet $A_{LL}$ preliminary results, this data use $\sim$40\% of the total 2013 data. The 2013 results are consistent with the published STAR dijet $A_{LL}$ measurements at $\sqrt{s}$ = 200 GeV, and the preliminary 2012 dijet $A_{LL}$. The 2013 dijet $A_{LL}$ is also consistent with global fits from DSSV and NNPDF collaborations, that incorporate the published STAR inclusive jet $A_{LL}$ at $\sqrt{s}$ = 200 GeV.