Berlin 2005 – scientific programme

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HK: Physik der Hadronen und Kerne

HK 26: Theorie

HK 26.4: Talk

Tuesday, March 8, 2005, 15:15–15:30, TU MA004

Dilepton production from hot hadronic matter in nonequilibrium — •Bjoern Schenke and Carsten Greiner — Institut fuer Theoretische Physik, Johann Wolfgang Goethe Universitaet, Robert-Mayer-Str. 10, 60054 Frankfurt am Main

We investigate medium modifications of low mass vector mesons in heavy ion collisions within a nonequilibrium quantum field theoretical description. In particular the emphasis lies on studying the fundamental question whether an adiabatic, i.e. instantaneous adaption of the dynamic and spectral information to the changing medium, as assumed in schematic model calculations and microscopic transport simulations, is a valid assumption. A significant retardation of the meson’s spectral function and the resulting dilepton rate is found, increasing with smaller vacuum widths. This results in remarkable effects on the total dilepton yield, especially within the range where the CERES experiment measured an increased production. Our findings show that an exact treatment of medium modifications requires the consideration of memory effects, and hence is more complicated than commonly assumed.