CPOD International Workshop at GSI Darmstadt
July 9 - 13, 2007 -
Registered Participants Information

Title:	Dr.
Last Name:	Cozma
First Name:	Dan
E-Mail:	cozmaniham.nipne.ro
Affiliation for Badge:	NIPNE, Bucharest
Institute:	NIPNE
Address (Street):	Atomistilor 407
Postal Code, City:	077125 Magurele, Bucharest
Country:	Romania
Phone:	0040-(0)21-4042311/4350
Fax:	0040-(0)21-4574440
Arrival Date:	July 8
Departure Date:	July 15
Hotel Information:	Others...
Payment:	Cash at the conference site
Contribution
Author(s):	M.D. Cozma(a), C. Fuchs(b), E. Santini(b), M. Petrovici(a)
Institute(s):	(a)NIPNE, 077125 Magurele-Bucharest, Romania (b)Universitat Tuebingen, Auf der Morgenstelle 14, 72076 Tuebingen, Germany
Title:	In-medium effects and dilepton emission in heavy-ion collisions at SIS energies
Abstract:	Heavy-ion reactions present an unique opportunity for the study of nuclear matter under extreme conditions allowing a comprehensive analysis of the phase structure of QCD. Electromagnetic probes, such as dileptons, could provide a clear view of the effective degrees of freedom at high baryon density and temperature, by reaveling information about chiral restoration and in-medium properties of hadrons. The Tuebingen model for dilepton emission is based on a nucleon resonance dominance model (NRD) in combination with an extended vector meson dominance (eVMD). NRD assumes that vector meson production runs over excitation of nucleon resonances while eVMD introduces radially excited $\rho$ and $\omega$ mesons in the radiative meson decays and $RN\gamma$ transition form factors, allowing a unified description of R->NV, R->N$\gamma$, $\gamma$N -> Ne and R -> Ne$^{+}$e$^{-}$ reactions. The properties of the $\rho$ and $\omega$ vector mesons in nuclear matter are studied by the determination of their in-medium spectral functions within the NRD+eVMD model. Comparison with the Brown-Rho scaling/collisional-broadening scenario reveals important differences. Embedded within the framework of the QMD transport model the NRD+eVMD model is used to evaluate dilepton production rates in heavy-ion collisions at SIS energies. Experimental data obtained by the DLS and HADES collaborations support the picture of complex medium modification of vector meson properties along the lines of the in-medium spectral functions scenario.