Transverse-Momentum and Collision-Energy Dependence of High-p_THadron Suppression in Au + Au Collisions at Ultrarelativistic Energies

We report high statistics measurements of inclusive charged hadron production in Au + Au and p + p collisions at √s_NN = 200 GeV. A large, approximately constant hadron suppression is observed in central Au + Au collisions for 5<p_T<12 GeV=c. The collision energy dependence of the yields and the centrality and p_T dependence of the suppression provide stringent constraints on theoretical models of suppression. Models incorporating initial-state gluon saturation or partonic energy loss in dense matter are largely consistent with observations. We observe no evidence of p_T-dependent suppression, which may be expected from models incorporating jet attenuation in cold nuclear matter or scattering of fragmentation hadrons.