Mach cone signal and energy deposition scenarios in linearized hydrodynamics

Abstract

Particle correlation measurements associated with a hard or semihard trigger in heavy-ion collisions may reflect Mach cone shock waves excited in the bulk medium by partonic energy loss. This is of great interest because, when compared with theory, such measurements can provide information on the transport properties of the medium. Specifically, the formation of Mach cone shock waves is sensitive to the viscosity and speed of sound, as well as the detailed nature of the jet-medium interaction. However, modeling the physics of shock-wave excitation to obtain a meaningful comparison with measured correlations is very challenging, as the correlations arise from an interplay of perturbative as well as nonperturbative phenomena at different momentum scales. In this work we take a step in that direction by presenting a systematic study of the dependence of azimuthal particle correlations on the spatiotemporal structure of energy deposition into the medium. Our results indicate that detailed modeling of the evolution of an initially produced hard parton and the interaction of this evolving state with the medium is crucial, as both the magnitude and the shape of the shock-wave signal show a strong dependence on the assumptions being made.