Electromagnetic emissivity of hot and dense matter

Abstract

The Quantum‐Chromo Dynamics (QCD) matter produced initially in ultrarelativistic nucleus–nucleus collisions is expected to represent a high temperature plasma, which should be evidenced in its electromagnetic radiation. We analyze the production of real and virtual photons from the strongly coupled Quark‐Gluon Plasma (QGP) in the initial stages of the collisions as well as the (“corona”) radiation from the interacting mesons and baryons after hadronization using the parton‐hadron‐string dynamics (PHSD) transport approach. The description of the bulk evolution in the microscopic PHSD approach has been independently controlled by abundances, spectra, and flow of final particles and is found to be in agreement with experimental observation. In this study, we provide a brief description of the relevant physics assumptions within the PHSD approach and give details on the implementation of real and virtual photon radiation in partonic and hadronic interactions and decays. Our calculations have been found to successfully describe the production of photons and dileptons in proton–proton as well as nucleus–nucleus collisions in a wide range of bombarding energies as well.