Photon production and screening properties of the QGP from lattice QCD

Abstract

In this work, properties of the quark-gluon plasma are studied, in particular thermal screening masses and the photon production rate. We employ the numerical realization of Quantum Chromodynamics (QCD) called lattice QCD. To the end of calculating screening masses and the rate of photon emission we generate lattice gauge ensembles at temperatures of 254 and 508 MeV well above the chiral and deconfinement phase transition temperature Tc ≈ 155 MeV at vanishing net baryon chemical potential and measure the relevant observables on the gauge configurations. The lattice regularized action contains the Wilson gauge action and the O(a) improved Wilson fermions with Nf = 2 mass degenerate light flavors. The generation of the finite-temperature ensembles is performed after careful tuning of the lattice and algorithmic parameters. The ensemble at 254 MeV enables a continuum extrapolated estimation of the photon emission rate from the quark-gluon plasma where we use two further ensembles at the same temperature that were previously generated within the Mainz lattice group.