Phenomenology of photon and di-lepton production in relativistic nuclear collisions

Abstract

We discuss the latest theoretical results on direct photon and dilepton production from relativistic heavy-ion collisions. While the dilepton spectra at low invariant mass show in-medium effects like a collisional broadening of the vector meson spectral functions, the dilepton yield at high invariant masses (above 1.1 GeV) is dominated by QGP contributions for central heavy-ion collisions at relativistic energies. The present status of the photon $v_2$ "puzzle" - a large elliptic flow $v_2$ of the direct photons experimentally observed at RHIC and LHC energies - is also addressed. The role of hadronic and partonic sources for the photon spectra and $v_2$ is considered as well as the possibility to subtract the QGP signal from the experimental observables.