Radiative energy loss of high energy quarks and gluons in a finite-volume quark-gluon plasma

The medium induced energy loss spectrum of a quark or gluon of high energy E traversing a hot QCD medium of finite volume is studied. We model the interaction by a simple picture of static scattering centres. The total induced energy loss is found to grow as L2, where L is the extent of the medium. This quadratic behaviour holds for L smaller than a critical length Lcr α √E. The solution of the energy loss problem is reduced to the solution of a Schrödinger-like equation whose “potential” is given by the single-scattering cross section of the high energy parton in the medium. These results should be directly applicable to a quark-gluon plasma.