Interplay between Mach cone and radial expansion and its signal in $γ$-jet events

Abstract: We study the hydrodynamic response to jet quenching in expanding quark-gluon plasma (QGP) and its signal in the resulting particle distribution. The ideal hydrodynamic simulations of the $\gamma$-jet events in heavy-ion collisions are performed in a full (3 + 1)-dimensional setup. The jet-induced Mach cone and the radial expansion of the background mutually push and distort each other. As a result, the particle emission is suppressed in the direction in which the radial flow is pushed back by the Mach cone when the jet path is an off-central one. This is the direct signal of hydrodynamic response to the jetand, moreover, includes information about the jet path in the expanding QGP fluid.