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

TLDR

While similar to the successful NL3 parameter set, the model yields a considerably softer equation of state for symmetric nuclear matter and symmetry energy, which is required to accurately describe collective modes with varying neutron‑to‑proton ratios. The authors introduce an accurately calibrated relativistic parametrization to compute the ground‑state properties of finite nuclei, their linear response, and the structure of neutron stars. The model examines how the softer equation of state impacts various neutron‑star properties. It predicts a symmetric nuclear‑matter incompressibility of K = 230 MeV and a neutron‑skin thickness of 0.21 fm in 208Pb.

Abstract

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 MeV and a neutron skin thickness in 208 Pb of Rn-Rp=0.21 fm. The impact of such a softening on various neutron-star properties is also examined.