Prof. David Blaschke (JINR Dubna)
We investigate the effectve repulsive interaction of Pauli blocking due to quark exchange among nucleons in nuclear matter within a nonrelativistic potential model for the nucleons. In order to describe nuclear saturation properties the nucleons are coupled to scalar and vector meanfields in the spirit of a linear Walecka model. The effects of chiral symmetry restoration is studies by adopting density-dependent quark masses that follow either the Brown-Rho scaling or the behaviour of a NJL model with 8-quark interaction terms (hNJL). When compared to the results for density-independent quark masses a strong density-dependent stiffening of the nuclear matter is obtained. The resulting symmetric nuclear matter equation of state is compared with results for the excluded-volume corrected density-dependent relativistic mean-field model DD2. Applications to neutron matter as well as to neutron star matter in beta-equilibrium are studied. The phase transition to quark matter described by the hNJL model is constructed and hybrid star sequences are obtained that form a third family of compact stars at high mass.