Lepton pair production in heavy ion collisions and hadronic phenomenology

Abstract

We first review the calculations of low invariant mass dilepton production in relativistic heavy ion collisions, using effective hadronic Lagrangians. We go through some of the theoretical techniques used in this kinematical region and we consider some of the appropriate experimental measurements. Moving up to the intermediate invariant mass region, we point out some of the uncertainties that show up in theoretical estimates. Those originate mainly from off-shell effects. Finally, as an application of hadronic chiral Lagrangians at finite temperature, we compute the mass shifts and mixing of the omega and phi mesons due to scattering from thermal pions.