Abstract :
Comparing dilepton data from Au+Au to p+p collisions at RHIC energies PHENIX revealed two striking features: (i) a large excess of the dilepton yield at low mass and low pT in central Au+Au and (ii) a significant enhancement of direct real photon radiation. Both features can be interpreted as thermal radiation from the hot quark matter produced at RHIC. Unlike at lower beam energies, at RHIC the contribution from the hot hadronic phase alone seems insufficient to account for the data. This suggests large a contribution from a partonic phase. Both experimental and theoretical progress are required for more detailed conclusions.
