The influence of flow on the jet quenching power in heavy-ion collisions

The flow pattern and evolution of the medium created in ultrarelativistic heavy ion collisions can have significant influence on the energy loss of hard partons traversing the medium. We demonstrate that within a range of assumptions for longitudinal and transverse flow which are all compatible with the measured hadronic single particle distributions, the quenching power of the medium can vary within a factor five. Thus, the choice of the medium evolution is one of the biggest uncertainties in jet quenching calculations and needs to be addressed with some care. (author)