Can the PREX-2 and CREX results be understood by relativistic mean-field models with the astrophysical constraints?

Abstract

We construct new effective interactions using the relativistic mean-field models with the isoscalar- and isovector-meson mixing, σ2δ2 and ωμωμρνρν. Taking into account the particle flow data in heavy-ion collisions, the observed mass of PSR J0740+6620, and the tidal deformability of a neutron star from the binary merger event, GW170817, we study the ground-state properties of finite, closed-shell nuclei, and try to explain the recent results from the PREX-2 and CREX experiments. It is found that the σ–δ mixing is very powerful to understand the terrestrial experiments and astrophysical observations of neutron stars self-consistently. We can predict the large neutron skin thickness of 208Pb, Rskin208=0.243 fm, using the slope parameter of nuclear symmetry energy, L=70 MeV, which is consistent with the PREX-2 result. However, to explain the CREX data, it is preferable to adopt the small value of L=20 MeV. It is very difficult to understand the PREX-2 and CREX results simultaneously within relativistic mean-field models.

Keywords

• Relativistic mean-field models
• PREX-2 and CREX experiments
• Isospin-asymmetric nuclear matter
• Neutron stars