Probing Longitudinal and Transverse Spin of Proton at PHENIX

by Amaresh Datta (University of Hawaii at Manoa)

Tuesday Dec 1, 2015, 3:00 PM → 4:00 PM Pacific/Honolulu

112 (WAT)

Since the time the EMC collaboration showed that the quarks carry only a small fraction of the proton spin, there has been interest in the particle physics community to better understand the proton spin structure. DIS experiments were of limited help. Hadron-hadron collision experiments like PHENIX and STAR has since probed the gluon helicity distribution inside proton to improve the understanding of proton spin structure. In the probed Bjorken-x range, the gluon contribution was found to be small. In recent years, there has also been exciting developments in the transverse spin scenario. Experiments measured large transverse asymmetries in contradiction to theoretical expectations, leading to focussed attempts to understand the phenomenon. Various mechanisms were proposed to explain the large asymmetries. Both at RHIC and at DIS experiments (COMPASS, HERMES), there is an ongoing effort to probe the prediction from these mechanisms that for comparable kinematics, the transverse single spin asymmetry (A_N) is process-dependent and that A_N(p+p) = -A_N(DIS).