EP Seminar

Electromagnetic Radiation from a Quark Gluon Plasma

by Dr Alberica Toia (Organisation européenne pour la recherche nucléaire (CERN))

500/1-001 - Main Auditorium (CERN)

500/1-001 - Main Auditorium


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PHENIX has measured an enhanced production of e+e- pairs In the low mass region, below the phi meson, in Au+Au collisions at sqrt(s_NN)=200GeV. At low mass and high p_T the mass shape of the excess is used to deduce the invariant yield of real direct photons. In central Au+Au the excess of direct photons above the photon yield in p+p is exponential with an inverse slope of T = 221 +/- 19(stat) +/- 19(syst) MeV, higher than the one predicted by lattice QCD for a phase transition. At low mass and low p_T the Au+Au spectrum shows a further significant enhancement, under-predicted by theoretical models, that increases with centrality and has an inverse slope of T~100 MeV, lower than that of hadrons with similar mass and similar to the freeze-out temperature. [arXiv:0912.0244]
Joint EP/PP seminar - 2009
Organized by

Maria Spiropulu / PH-EP ------------------------------------ ** Tea and coffee will be served at 10:30