ar X iv : h ep - t h / 06 07 08 9 v 1 1 3 Ju l 2 00 6 The Energy of a Moving Quark - Antiquark Pair in an N = 4 SYM Plasma

We make use of the AdS/CFT correspondence to determine the energy of an external quark-antiquark pair that moves through strongly-coupled thermal N = 4 super-Yang-Mills plasma. It is found that the pair feels no drag force, has an energy that reproduces the expected √ 1− v/L behavior at small quarkantiquark separations, and becomes unbound beyond a certain screening length whose velocity-dependence we determine. We discuss the relation between the high-velocity limit of our results and the lightlike Wilson loop proposed recently as a definition of the jet-quenching parameter.