Photon and dilepton production from a non-equilibrium quark-gluon plasma

Abstract

We calculate leading-order medium photon and dilepton yields from a quark-gluon plasma using (3+1)-dimensional anisotropic hydrodynamics. In the case of dileptons, at leading-order it is sufficient to take into account non-equilibrium corrections to the rate through the use of anisotropic distribution functions. In the case of photons, non-equilibrium corrections to the rate are taken into account using a self-consistent modification of the distribution functions and the corresponding anisotropic hard-loop quark self-energies. We present predictions for the high-energy photon and dilepton spectrum and the photon elliptic flow as a function of invariant mass, transverse momentum, shear viscosity, and initial momentum-space anisotropy. Our findings indicate that both high-energy photon and dilepton production are sensitive to the assumed level of initial momentum-space anisotropy of the quark-gluon plasma. In addition, we find that the photon elliptic flow depends on the initial momentum-space anisotropy.