The effect of momentum deposition during fireball evolution on flow anisotropy

TL;DR

This paper demonstrates that including momentum deposition during fireball evolution in hydrodynamic simulations significantly affects flow anisotropy, especially elliptic flow, in high-energy collisions at the LHC.

Contribution

It introduces the necessity of modeling momentum deposition during fireball evolution in 3+1D hydrodynamics, which was not accounted for by initial conditions alone.

Findings

Momentum deposition increases elliptic flow in non-central collisions.

Flow anisotropy is correlated with fireball geometry.

Energy and momentum deposition scenarios show consistent effects.

Abstract

The highest LHC energies give rise to production of many pairs of hard partons which deposit four-momentum into the expanding fireball matter. We argue that it is necessary to include momentum deposition during fireball evolution into 3+1 dimensional hydrodynamic simulations of the collision. This influence cannot be accounted for simply by modifying initial conditions of the simulation. The resulting contribution to flow anisotropy is correlated with the fireball geometry and causes an increase of the elliptic flow in non-central collisions. The results are presented for various scenarios with energy and momentum deposition to clearly demonstrate this effect.