Speaker
Description
Radiation of photons is a promising and efficient tool to study the initial state of heavy-ion collisions. Unlike hadrons, photons are emitted during all stages of the expanding fireball and, due to their electromagnetic nature, they do not suffer further interaction with the medium, carrying undistorted information about the circumstances of their production. In this talk we discuss spectrum and elliptic flow of photons emitted from the quark-gluon plasma produced in heavy ion collisions, both at LHC and RHIC energies. Simulating the space-time evolution of the fireball by solving the relativistic Boltzmann transport equation and including two particle scattering processes with photon emission allows as to make a first step in the description of thermal photons from the QGP as well as of those produced in the pre-equilibrium stage. Indeed, we consider not only a standard Glauber initial condition but also a model in which partons are produced through the Schwinger mechanism by the decay of an initial color-electric field. In the latter approach relativistic kinetic equations are coupled in a self-consistent way to the chromo-electric field equations. We aim at spotting the impact of early stage non-equilibrium dynamics on the photon production.
