Dilepton production in the strongly interacting quark-gluon plasma

Dilepton production in relativistic heavy ion collisions is studied within the microscopic Parton-Hadron-Strings Dynamics (PHSD) transport approach, which is based on a dynamical quasiparticle model (DQPM) matched to reproduce lattice QCD results in thermodynamic equilibrium. A comparison to the data of the NA60 Collaboration on the In+In collisions at 158 A⋅GeV shows that the dilepton spectra are well described by the sum of hadronic and partonic sources, if a collisional broadening of vector mesons is taken into account as well as the off-shell quark-antiquark annihilation ( and ) in the QGP. In particular, the observed softening of the mT spectra at intermediate masses is reproduced. The data of PHENIX collaboration on dilepton production in Au+Au collisions at at masses above 1 GeV/c2 are found to be dominated by the contributions of the QGP radiation and the charm meson decays, while the measured spectrum is underestimated in the mass range from 0.2 to 0.6 GeV/c2.