Neutral Pions with Large Transverse Momentum in d+Au and Au+Au Collisions

Abstract

Measurements of transverse-momentum p_T spectra of neutral pions in Au+Au and d+Au collisions at sqrt{s_NN}=200 GeV and 62.4 GeV by the PHENIX experiment at RHIC in comparison to p+p reference spectra at the same sqrt{s_NN} are presented. In central Au+Au collisions at sqrt{s_NN}=200 GeV a factor 4-5 suppression for neutral pions and charged hadrons with p_T > 5 GeV/c is found relative to the p+p reference scaled by the nuclear overlap function . In contrast, such a suppression of high-p_T particles is absent in d+Au collisions independent of the centrality of the collision. To study the sqrt{s_NN} dependence of the suppression Au+Au collisions at sqrt{s_NN}=200 GeV and 62.4 GeV are compared.Comment: 7 pages, 5 figures, presented at Hot Quarks 2004, Taos, N