Semiclassical transport of particles with dynamical spectral functions

The conventional transport of particles in the on-shell quasiparticle limit is extended to particles of finite life time by means of a spectral function A(X, P,M ²) for a particle moving in an area of complex self-energy Σ ^ret_X= Re Σ ^ret_X-iΓ _X/2 . Starting from the Kadanoff—Baym equations we derive in first-order gradient expansion equations of motion for testparticles with respect to their time evolution in X, P and M². The off-shell propagation is demonstrated for a couple of model cases that simulate hadron-nucleus collisions. In case of nucleus-nucleus collisions the imaginary part of the hadron self-energy Γ_X is determined by the local space-time dependent collision rate dynamically. A first application is presented for A+ A reactions up to 95 A MeV, where the effects from the off-shell propagation of nucleons are discussed with respect to high energy proton spectra, high energy photon production as well as kaon yields in comparison to the available data from GANIL.