Speaker
Dr
Itaru Nakagawa
(RIKEN/RBRC)
Description
A primary goal of the RHIC Spin program has been to measure $Delta g$, the gluon spin contribution to the proton spin, through the double helicity asymmetry, $A_{LL}$. The PHENIX detector is designed with very good electromagnetic calorimetery, allowing for a high statistics $\pi^0$ $A_{LL}$ measurement. PHENIX results from 2005 and 2006 at $\sqrt{s}=200$ GeV have been used in the DSSV global analysis, and were shown to significantly constrain $Delta g$. PHENIX also has made measurements of charged pion, direct photon and heavy flavor $A_{LL}$. Measurements of neutral pions at large rapidity ($3.1<|\eta|<3.9$) will significantly extend the $x$ range probed in PHENIX towards lower $x$. Analysis is also underway for these channels in the large $\sqrt{s}=500$ GeV data taken in 2011-2013. The status of the PHENIX $A_{LL}$ measurements will be presented, including the final results for the 2009 $\pi^0$ $A_{LL}$ at $\sqrt{s}=200$ GeV.
Author
Dr
Itaru Nakagawa
(RIKEN/RBRC)
