Centrality dependence of the high p_T charged hadron suppression in Au+Au collisions at √s_NN= 130 GeV

Abstract

PHENIX has measured the centrality dependence of charged hadron p_T spectra from Au+Au collisions at √s_NN= 130 GeV. The truncated mean p_T decreases with centrality for p_T>2 GeV/c, indicating an apparent reduction of the contribution from hard scattering to high pT hadron production. For central collisions the yield at high pT is shown to be suppressed compared to binary nucleon-nucleon collision scaling of p+p data. This suppression is monotonically increasing with centrality, but most of the change occurs below 30% centrality, i.e., for collisions with less than |140 participating nucleons. The observed pT and centrality dependence is consistent with the particle production predicted by models including hard scattering and subsequent energy loss of the scattered partons in the dense matter created in the collisions.