Pre-equilibrium photons from the early stages of heavy-ion collisions

2023/08/18 by Garcia-Montero, Oscar, Mazeliauskas, Aleksas, Plaschke, Philip +1 · 2 citations
#FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #Nuclear Theory (nucl-th)

paper · doi:10.48550/arxiv.2308.09747

Abstract

We use QCD kinetic theory to compute photon production in the chemically equilibrating Quark-Gluon Plasma created in the early stages of high-energy heavy-ion collisions. We do a detailed comparison of pre-equilibrium photon rates to the thermal photon production. We show that the photon spectrum radiated from a hydrodynamic attractor evolution satisfies a simple scaling form in terms of the specific shear viscosity η/s and entropy density dS/dζ∼ \scriptstyle (Tτ^1/3)^3/2_∞. We confirm the analytical predictions with numerical kinetic theory simulations. We use the extracted scaling function to compute the pre-equilibrium photon contribution in √s_NN=2.76 TeV 0-20% PbPb collisions. We demonstrate that our matching procedure allows for a smooth switching from pre-equilibrium kinetic to thermal hydrodynamic photon production. Finally, our publicly available implementation can be straightforwardly added to existing heavy ion models.

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• Jet quenching in out-of-equilibrium QCD matter
• Bayesian Constraints on Pre-Equilibrium Jet Quenching and Predictions for Oxygen Collisions

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