Measurement of Drell-Yan longitudinal double spin asymmetry in polarized p + p collisions at PHENIX

Measurement of the longitudinal double spin asymmetry ($A_{LL}$) in the Drell-Yan process in high energy polarized proton-proton collisions provides clean access to the anti-quark helicity distributions in the proton without involving quark fragmentation functions. In the PHENIX experiment at RHIC, the Forward Silicon Vertex Detector (FVTX) together with the forward muon spectrometers have been used to study the Drell-Yan process by detecting the muon pairs in the forward region (1.2 $< \eta <$ 2.4). In this talk, the status of evaluating the Drell-Yan signal fraction and the $A_{LL}$ asymmetry in the intermediate mass region (4.5 GeV $< M <$ 8 GeV) using the RHIC 2013 dataset of proton-proton collisions at a center of mass energy of 510 GeV are presented.