Flow dependence of high pT parton energy loss in heavy-ion collisions -: art. no. 044901

The measured transverse momentum spectra and HBT correlations of bulk (i.e., low p(T)) matter can be well explained by assuming that the soft sector of particles produced in ultrarelativistic heavy-ion collisions is (approximately) thermalized and undergoes collective accelerated expansion in both longitudinal and transverse direction. However, this implies that bulk matter will have a nonvanishing flow component transverse to the trajectory of a high p(T) partonic jets. In general, this will increase the energy loss experienced by the jet parton and modify the shape of the jet cone. In this paper, we present a systematic study of the magnitude of the additional energy loss induced by flow under realistic assumptions for the medium evolution. We argue that a perturbative QGP description may be sufficient for the measured R-AA if flow during the medium evolution is taken into account properly.