Study of the gluon polarization in the proton with a silicon vertex upgrade at RHICPHENIX.pdfVIP

February 7, 2008 7:52 Proceedings Trim Size: 9in x 6in spin2004 5 0 0 2 STUDY OF THE GLUON POLARIZATION IN THE PROTON WITH A SILICON VERTEX UPGRADE AT RHIC/PHENIX n a J 8 M.TOGAWA FOR THE PHENIX COLLABORATION 1 Kyoto University, Kyoto, 606-8502, JAPAN. 1 Radiation Laboratory, RIKEN, Wako, Saitama, 351-0198, JAPAN. v E-mail: togawa@nh.scphys.kyoto-u.ac.jp 7 4 Abstract. PHENIX has a well defined program for measuring the polarized gluon 0 distribution in the nucleon. The measurements of gluon polarization via the direct- 1 photon production and the heavy-flavor production can be significantly improved 0 by the silicon vertex tracker upgrade. We have studied the possible improvements 5 of the gluon polarization measurements using Monte Carlo simulation and they 0 are shown and discussed in this paper. / x e 1. Introduction - p One of the major goals of the PHENIX experiment at the Relativistic Heavy e h Ion Collider (RHIC) is a determination of the gluon polarization in the : proton 1 . We have measured the double longitudinal-spin asymmetry ALL √ v 0 i of π production in longitudinally polarized p-p collisions at s = 200 GeV X 2 . In this process, π0 carries only fraction of the momentum of the scattering