Bulk viscous corrections to photon production in the quark-gluon plasma

TL;DR

This paper calculates the impact of bulk viscous corrections on photon production in the quark-gluon plasma, providing more accurate predictions for photon observables in heavy-ion collisions.

Contribution

It explicitly evaluates phase-space integrals for bulk viscous corrections without relying on the forward scattering approximation, improving accuracy for photon production calculations.

Findings

Bulk viscous corrections reduce photon elliptic flow at high transverse momentum.

Explicit phase-space integral evaluation improves the precision of photon production models.

Hydrodynamical simulations show significant effects of bulk corrections on photon observables.

Abstract

Photons radiated in heavy-ion collisions are a penetrating probe, and as such can play an important role in the determination of the quark-gluon plasma (QGP) transport coefficients. In this work we calculate the bulk viscous correction to photon production in two-to-two scattering reactions. Phase-space integrals describing the bulk viscous correction are evaluated explicitly in order to avoid the forward scattering approximation which is shown to be poor for photons at lower energies. We furthermore present hydrodynamical simulations of AA collisions focusing on the effect of this calculation on photonic observables. Bulk corrections are shown to reduce the elliptic flow of photons at higher $p_T$.