Modelling the Impact of Path-Length and Energy-Loss Fluctuations on Jet-Like Correlations

The question of how QCD jets interact with a QGP medium as a function of path-length is a significant ongoing research effort in the relativistic heavy ion community. However, it has been demonstrated that jet-by-jet fluctuations in the jet-medium interactions may dominate measurements intended to study the path-length dependence, such as dijet asymmetry. In this study, we use the JEWEL model of jet-medium interaction to study how this applies to two-particle correlations as a function of the angle with the reaction plane. In particular, we study dihadron correlations in dijet events and direct photon-hadron correlations in photon-jet events. In the latter case, the contribution from jet-medium interaction fluctuations to observables is suppressed, as there is only one jet and the direct photon leaves the medium unaffected. We demonstrate that such direct photons can provide an optimal window into path-length dependence. By studying the yield and widths of the awayside and nearside peaks, we make predictions for such measurements in heavy ion collisions at RHIC and LHC energies.