Dileptons and photons produced in relativistic heavy ion collisions at SPS, RHIC and LHC

We address the dilepton and photon production by the (in-medium) mesons, correlated decays of charm and bottom quarks and the quark and gluon interactions in the early stage of relativistic heavy-ion collisions within the parton-hadron-string dynamics (PHSD) off-shell transport approach. The approach treats the full evolution of a relativistic heavy-ion collision from the initial hard scatterings and string formation through the dynamical deconfinement phase transition to the strongly interacting quark-gluon plasma (QGP) as well as hadronization and to the subsequent interactions in the hadronic phase. We study the dilepton yield from the collisions at energies from SPS to RHIC to LHC. By comparing to the data of the NA60, PHENIX and STAR Collaborations, we determine the relative importance of the different dilepton production mechanisms and point out the regions in phase space where partonic channels are dominant. Explicit predictions are presented for dileptons from the Pb+Pb collisions at sqrt(s)=2.76 TeV. Additionally, the photon production under the influence of the strong magnetic fields in the initial stage of the collision is discussed.