Jet quenching in the direction opposite to a tagged photon in high-energy heavy-ion collisions

We point out that events associated with large E(T) direct photons in high-energy heavy-ion collisions can be used to study jet energy loss in dense matter. In such events, the p(T) spectrum of charged hadrons from jet fragmentation in the direction opposite to the tagged photon is estimated to be well above the background which can be reliably subtracted at moderately large p(T). We demonstrate that comparison between the extracted fragmentation function in AA and pp collisions can be used to determine the jet energy loss and the interaction mean free path in the dense matter produced in high-energy heavy-ion collisions.