Boris Kopeliovich

"Jet quenching: a fresh look at the energy loss scenario"

 The popular energy loss scenario explaining the observed suppression
 of high-pT hadrons produced in heavy ion collisions relies upon poorly
 justified assumptions. First, one assumes that gluon radiation and energy
 loss are continuing through the medium and end far outside. Second, the
 standard prescription for incorporating energy loss induced by multiple
 interactions in the medium is to make a shift of the variable in the
 fragmentation function. This implies that the hadronization starts only
 at the medium surface. We challenge both assumptions. We calculate the
 upper bound for the modification of the fragmentation function via the
 medium driven DGLAP evolution. The effects are found to be too weak to
 explain available data and quite different from what is suggested by
 the standard energy loss scenario.