Effective distributions of quasi-particles for thermal photons

TL;DR

This paper develops effective quasi-particle distributions aligned with lattice QCD to improve modeling of thermal photon flow in heavy-ion collisions, addressing discrepancies in experimental observations.

Contribution

It introduces in-medium interaction-based quasi-particle distributions consistent with lattice QCD, enhancing thermal photon flow predictions in hydrodynamic models.

Findings

Modified elliptic flow and transverse momentum spectra of thermal photons.

Corrections to Fermi-Dirac and Bose-Einstein distributions impact photon observables.

Improved agreement with experimental data on photon flow.

Abstract

It has been found in recent heavy-ion experiments that the second and the third flow harmonics of direct photons are larger than most theoretical predictions. In this study, I construct effective parton phase-space distributions with in-medium interaction using quasi-particle models so that they are consistent with a lattice QCD equation of state. Then I investigate their effects on thermal photons using a hydrodynamic model. Numerical results indicate that elliptic flow and transverse momentum spectra are modified by the corrections to Fermi-Dirac and Bose-Einstein distributions.