Neutron-Rich Nuclei and Neutron Stars: A New Accurately Calibrated Interaction for the Study of Neutron-Rich Matter

An accurately calibrated relativistic parametrization is introduced to compute the ground state properties of finite nuclei, their linear response, and the structure of neutron stars. While similar in spirit to the successful NL3 parameter set, it produces an equation of state that is considerably softer—both for symmetric nuclear matter and for the symmetry energy. This softening appears to be required for an accurate description of several collective modes having different neutron-to-proton ratios. Among the predictions of this model are a symmetric nuclear-matter incompressibility of $K=230\mathrm{MeV}$ and a neutron skin thickness in ${}^{208}\mathrm{P}\mathrm{b}$ of $R_n-R_p=0.21\mathrm{fm}$. The impact of such a softening on various neutron-star properties is also examined.