Latest documents http://publikationen.ub.uni-frankfurt.de/index/index/ Mon, 14 Nov 2005 10:38:37 +0100 Mon, 14 Nov 2005 10:38:37 +0100 http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/3303 A significant drop of the vector meson masses in nuclear matter is observed in a chiral SU(3) model due to the e ects of the baryon Dirac sea. This is taken into account through the summation of baryonic tadpole diagrams in the relativistic Hartree approximation. The appreciable decrease of the in-medium vector meson masses is due to the vacuum polarisation e ects from the nucleon sector and is not observed in the mean field approximation. Detlef Zschiesche; Amruta Mishra; Stefan Schramm; Horst Stöcker; Walter Greiner preprint http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/3303 Mon, 14 Nov 2005 10:38:37 +0100 http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/3324 We evaluate the in-medium D and -meson masses in hot hadronic matter induced by interactions with the light hadron sector described in a chiral SU(3) model. The e ective Lagrangian approach is generalized to SU(4) to include charmed mesons. We find that the D-mass drops substantially at finite temperatures and densities, which open the channels of the decay of the charmonium states ( 2, c, J/ ) to D pairs in the thermal medium. The e ects of vacuum polarisations from the baryon sector on the medium modification of the D-meson mass relative to those obtained in the mean field approximation are investigated. The results of the present work are compared to calculations based on the QCD sum-rule approach, the quark-meson coupling model, chiral perturbation theory, as well as to studies of quarkonium dissociation using heavy quark potential from lattice QCD. Amruta Mishra; Elena L. Bratkovskaya; Jürgen Schaffner-Bielich; Stefan Schramm; Horst Stöcker preprint http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/3324 Thu, 10 Nov 2005 10:34:59 +0100