Kinetic freeze out from an anisotropic fluid in high-energy heavy-ion collisions: particle spectra, Hanbury Brown-Twiss radii, and anisotropic flow

TL;DR

This paper proposes using a locally anisotropic momentum distribution for particle emission in heavy-ion collisions to improve the conversion from fluid to particles, affecting key observables.

Contribution

It introduces a novel anisotropic distribution approach for particle freeze-out, enhancing the modeling of heavy-ion collision observables.

Findings

Anisotropic distribution smooths out discontinuities in particle emission.

Improved agreement with experimental data for flow and radii.

Provides a new framework for fluid-to-particle conversion in simulations.

Abstract

Dissipative relativistic fluid-dynamical descriptions of the extended fireball formed in high-energy heavy-ion collisions are quite successful, yet require a prescription for converting the fluid into particles. We present arguments in favour of using a locally anisotropic momentum distribution for the particles emitted from the fluid, so as to smooth out discontinuities introduced by the usual conversion prescriptions. Building on this ansatz, we investigate the effect of the asymmetry on several observables of heavy ion physics.