Sanja Damjanovic, "NA60 results on thermal dimuons"

vendredi 15 mai 2009, 15:00 → 16:00 Europe/Paris

Salle gradinée 9111

The NA60 experiment at the CERN SPS has studied muon-pair production in 158A GeV In-In collisions. A strong excess of pairs above the known sources is observed in the whole mass region 0.2<M<2.6 GeV. At around 1 GeV, the pT/mT spectra point to a transition from dominantly hadronic to dominantly partonic sources. For M<1 GeV, this has given access to the space-time averaged rho spectral function with its connection to chiral symmetry restoration, while for M>1 GeV, the findings directly link to confinement. The Planck-like shape of the mass spectra, mT scaling, zero polarization and the general agreement of the data with theoretical models allow for a consistent interpretation of the excess dimuons as thermal radiation.