PHENIX measurements of nuclear modification factor of hadrons in d+Au and A+A collisions.

Abstract

High momentum partons, traversing through the colored medium created in heavy ion collisions (A+A), lose significant amount of energy, resulting in suppression of high p T particle yields generally quantified by the 'nuclear modification factor (R AA )'. Particle production is also modified in the presence of cold nuclear matter effects which are studied in d+Au collisions, and quantified by a quantity R dAu . The quantities, R AA and R dAu are defined as the ratio of the yields in A+A and d+Au collisions respectively to the yield in p+p collisions, scaled by the number of binary collisions in respective collision systems. In this proceeding the recent R AA and R dAu results from PHENIX are presented, along with the comparison among the wide variety of particles, spanning from the light quark mesons(π 0 , π ± ), strange quark mesons (K ± , K 0 S , K * 0 , φ ), baryons (p) to the electrons from heavy flavor and direct photons.