Asymmetric nuclear matter and neutron star properties in relativistic ab initio theory in the full Dirac space

The long-standing controversy about the isospin dependence of the effective Dirac mass in ab initio calculations of asymmetric nuclear matter is clarified by solving the relativistic Brueckner-Hartree-Fock equations in the full Dirac space. The symmetry energy and its slope parameter at the saturation density are Esym(ρ0)=33.1 MeV and L=65.2 MeV, in agreement with empirical and experimental values. Further applications predict the neutron star radius R1.4M⊙≈12 km and the maximum mass of a neutron star Mmax≤2.4M⊙.