Dependence of energy loss of jets on the initial thermodynamic state of deconfined matter at RHIC

Abstract

The dependence of the radiative energy loss of fast partons on the initial thermodynamic parameters is studied for deconfined matter to be expected at RHIC. We demonstrate that the specific QCD radiation pattern with a quadratic dependence of the energy loss on the propagated distance leads to a strong increase of the energy loss with increasing initial entropy of deconfined matter supposed its life-time is less than the average time to pass through the medium. This is in contrast to a parameterization with constant energy loss per unit length of propagation. For a sufficiently high initial temperature a two-regime behavior of the energy loss as a function of the initial parton momentum occurs. The angular structure of the energy loss of hard jets with respect to the initial temperature is also discussed for RHIC conditions.