Hard Probe Measurements in Cu+Au Collisions at PHENIX: Jets and Leading Particles

Collision of asymmetric nuclei like Cu+Au provides the means to study hard probes in different collision geometry compared to collisions of symmetric nuclei like Cu+Cu and Au+Au. A systematic study of the production of high transverse momentum particles and jets in systems with different geometry may provide information about the path-length dependence of energy loss in the medium. The PHENIX experiment has measured the transverse momentum distributions and the nuclear modification factors, RAA of jets and leading particles, such as π0 mesons, in Cu+Au collisions at sNN=200 GeV. The jets are reconstructed with the anti-kT clustering algorithm with a distance parameter of R=0.2, chosen to minimize the contribution of the underlying event. The RAA measurements in Cu+Au collisions are presented as a function of pT and centrality and compared to theoretical calculations.