March 5 th, 2007-
Prof. Hans-Juergen Pirner
Institut fuer Theoretische Physik, Heidelberg
loss of a fast parton in the Quark Gluon Plasma
I discuss the strong coupling constant in the plasma. Is it changed and how? Then using a R.G. calculation of the strong coupling I calculate the parton-parton cross sections in the plasma and the collisional energy loss. The inverse Compton process is investigated and found to contribute 30%. Next I derive the radiative energy loss from the Bethe Heitler
cross section. I work out the temperature dependence of the two contributions
and their time dependence during the collision. Finally I emphasize that the fragmentation process also varies with the virtuality of the initial parton.