Energy loss of a heavy quark produced in a finite size medium

We study the medium-induced energy loss Delta E-0(L-p) suffered by a heavy quark produced at initial time in a quark-gluon plasma, and escaping the plasma after travelling the distance Lp. The heavy quark is treated classically, and within the same framework -Delta E-0(L-p) consistently includes: the loss from standard collisional processes, initial bremsstrahlung due to the sudden acceleration of the quark, and transition radiation. The radiative loss induced by rescatterings -Delta E-rad(L-p) is not included in our study. For a ultrarelativistic heavy quark with momentum p greater than or similar to 10 GeV, and for a finite plasma with L-p less than or similar to 5 fm, the loss -Delta E-0(L-p) is strongly suppressed compared to the stationary collisional contribution -Delta E-coll(L-p) alpha L-p. Our results support that -Delta E-rad is the dominant contribution to the heavy quark energy loss (at least for L-p less than or similar to 5 fm), as indeed assumed in most of jet-quenching analyses. However they might raise some question concerning the RHIC data on large p(perpendicular to) electron spectra.