Degrees of freedom and the deconfining phase transition

There is a sharp increase in the relative number of degrees of freedom at the deconfining phase transition. Characterizing this increase using the Polyakov Loop model, we find that for three colors, where there is a nearly second order deconfining phase transition, the medium-induced energy loss turns on rapidly above T-c. As expected, energy loss increases proportional to the relative number of degrees of freedom. In addition, however, there is a logarithmic dependence upon the screening mass, which changes markedly near the would be critical point. Thus this sensitivity to the screening mass can be used to probe non-ideal, nearly critical, behavior in the quark-gluon plasma. (C) 2002 Elsevier Science B.V. All rights reserved.