Photon emission from a parton gas at chemical nonequilibrium

Abstract

We compute the hard photon production rate of a chemically non-equilibrated quark-gluon plasma. We assume that the plasma is already thermally equilibrated, i. e. describable by a temperature, but with a phase-space distribution that deviates from the Fermi/Bose distribution by a time dependent factor (fugacity). The photon spectrum is obtained by integrating the photon rate over the space-time evolution of the quark-gluon plasma. Some consequences for ultrarelativistic heavy ion collisions are discussed.

Braaten-Pisarski method at finite chemical potential

“…The calculation of the hard photon production rate at finite quark chemical potential considering the effective quark propagator modified by the effective quark mass (6) will be presented in a in a forthcoming publication [33].…”

Thermal photons in QGP and non-ideal effects

“…Once the evolution of temperature is known from the hydrodynamical model, the total photon spectrum is obtained by integrating the total rate over the space time history of the collision [58],…”

Fermionic collective modes of an anisotropic quark-gluon plasma

“…In equilibrium this can be done self-consistently within the hard thermal loop framework [5][6][7] and there are now many papers dedicated to the calculation of equilibrium photon production at leading and next-toleading order [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27]. In addition, there have been calculations of electromagnetic signatures from a plasma which is not chemically equilibrated [28][29][30][31][32][33][34][35][36]. However, the problem of photon and dilepton production from a quark-gluon plasma which is not isotropic in momentum space has not yet been considered.…”