Theoretical Analysis of Dilepton Spectra in Heavy Ion Collisions at GSI-FAIR Energies

This paper addresses the theoretical analysis of dilepton spectra in C+C collisions at GSI-SIS energies. Theoretical predictions for the recent data of the HADES collaboration at SIS-energies are made with the help of a hadron-string transport model, the Ultra-relativistic Quantum Molecular Dynamics (UrQMD) model. A mass shift of the $\rho$ meson due to kinematical effects is discussed.