GENERALIZED BETH-UHLENBECK APPROACH FOR HOT NUCLEAR-MATTER

Properties of hot nuclear matter are studied by means of the thermodynamic Green's function approach under special consideration of the two-particle clustering in a nuclear environment. It has been found that the two-particle clustering is strongly suppressed due to Pauli blocking and quasiparticle effects if the density exceeds a critical value (Mott effect). The resulting equation of state exhibits the general form of a Beth-Uhlenbeck formula and contains the classical law of mass action and the Brueckner-Bethe-Goldstone theory as limiting cases for low and normal nuclear matter densities, respectively. The approach predicts two distinct phase transitions, a liquid-vapour phase transition and the onset of a transition to a superfluid phase. The calculations have been performed with a separable representation of the PARIS-potential which permits us to calculate in a convenient way such interesting quantities as the density dependent binding energies and scattering phase shifts, the abundance of correlated pairs and the density as a function of the temperature and the chemical potential. The in-medium nucleon-nucleon cross section and the mean free path of a nucleon within nuclear matter are given. © 1990.