A Tale of Tails: Photon Rates and Flow in Ultra-Relativistic Heavy Ion Collisions

TL;DR

This paper explores how high-energy tails in quark and gluon distributions, modeled by Tsallis functions, can enhance photon production and delay emission times in ultra-relativistic heavy ion collisions, potentially explaining experimental observations.

Contribution

It introduces a phenomenological model with Tsallis distributions to account for high-energy tails in parton spectra, affecting photon emission rates and timing.

Findings

High-energy tails increase photon production rates.

Delayed photon emission times align with experimental flow patterns.

Model explains observed photon yields in LHC and RHIC.

Abstract

We consider the possibility that quark and gluon distributions in the medium created in high energy heavy ion collisions may be modified by a power law tail at energies much higher than the temperature. We parametrize such a tail by Tsallis distributions with an exponent motivated by phenomenology. These distributions are characterized by an effective temperature scale that we assume to evolve in time like the temperature for thermal distributions. We find that including such a tail increases the rates for photon production and significantly delays the emission times for photons of a fixed energy. We argue that these effects are sufficiently large that they should be able to account for photon yields and flow patterns seen in LHC and RHIC experiments.