O ct 1 99 9 Semiclassical transport of hadrons with dynamical spectral functions in A + A collisions at SIS / AGS energies ∗

The transport of hadrons with dynamical spectral functions A h (X, P , M 2) is studied for nucleus-nucleus collisions at SIS and AGS energies in comparison to the conventional quasi-particle limit and the available experimental data within the recently developed off-shell HSD transport approach. Similar to reactions at GANIL energies the off-shell effects show up in high momentum tails of the particle spectra, however, at SIS and AGS energies these modifications are found to be less pronounced than at lower energies due to the high lying excitations of the nucleons in the collision zone.