Improving a radiative plus collisional energy loss model for application to RHIC and LHC

With the QGP opacity computed perturbatively and with the global entropy constraints imposed by the observed dNch/dy~1000, radiative energy loss alone cannot account for the observed suppression of single non-photonic electrons. Collisional energy loss is comparable in magnitude to radiative loss for both light and heavy jets. Two aspects that significantly affect the collisional energy loss are examined: the role of fluctuations, and the effect of introducing a running QCD coupling as opposed to the fixed alpha_s=0.3 used previously.