Impact of the energy loss spatial profile and shear viscosity to entropy density ratio for the Mach cone vs. head shock signals produced by a fast moving parton in a quark-gluon plasma

TL;DR

This paper investigates how the energy loss profile and shear viscosity to entropy density ratio affect the formation of Mach cone and head shock signals from a fast parton in a quark-gluon plasma, revealing that transverse modes dominate under various conditions.

Contribution

It introduces a detailed analysis of energy loss profiles and viscosity effects on shock signals in quark-gluon plasma using linear viscous hydrodynamics, extending previous models.

Findings

Transverse modes dominate energy deposition regardless of parameters.

Head-shock signals are prevalent across different energy loss profiles.

Lower shear viscosity favors head-shock dominance.

Abstract

We compute the energy and momentum deposited by a fast moving parton in a quark-gluon plasma using linear viscous hydrodynamics with an energy loss per unit length profile proportional to the path length and with different values of the shear viscosity to entropy density ratio. We show that when varying these parameters, the transverse modes still dominate over the longitudinal ones and thus energy and momentum is preferentially deposited along the head-shock, as in the case of a constant energy loss per unit length profile and the lowest value for the shear viscosity to entropy density ratio.