Longitudinal Double Spin Asymmetry and Cross Section for Direct Photon Production at Mid-rapidity in Polarized $\sqrt{s} = 200$ GeV $pp$ Collisions at PHENIX

Production of direct photons in collisions at RHIC is one of the important c hannels PHENIX will employ to determine the polarized gluon distribution. To es tablish the theoretical understanding of this process, we first present the comp arison the direct photon unpolarized cross section measured during $\sqrt{s} = 2 00$ GeV collisions, with the perturbative QCD calculations at next-to-leading or der. The extraction of the cross section relies on two techniques: First purify ing our sample by considering only isolated photons as direct photon candidates and second by a statistical subtraction of weighted spectra of known sources of decay photons from the total photon event sample. We then proceed to evaluate th e double helicity spin asymmetries, $A_{LL}$, from these data sets and compare w ith theoretical models. Since the direct photon $A_{LL}$ is linear in $\Delta G $, it is sensitive to both the sign and magnitude of $\Delta G$ and it will even tually be able to serve as a complementary measurement to the $\pi^0$ $A_{LL}$ a nalysis . A status of the analysis of data obtained in 2005, based on a luminos ity of $2.7$ pb$^{-1}$ and polarization 50\%, and 2006 with $7.5$ pb$^{-1}$ lumi nosity and $60\%$ polarization will be presented.