[Prex] Massive neutron stars with small radii in relativistic mean-field models optimized to nuclear ground states

[Jay Benesch]

https://arxiv.org/abs/2209.02861

Massive neutron stars with small radii in relativistic mean-field models optimized to nuclear ground states
Tsuyoshi Miyatsu, Myung-Ki Cheoun, Kyungsik Kim, Koichi Saito

    We present an equation of state (EoS) for neutron stars using the relativistic mean-field model with isoscalar- and isovector-meson mixing. Taking into account the results of the neutron skin thickness, Rskin, of 208Pb reported by the PREX collaboration, the dimensionless tidal deformability of a canonical neutron star observed from GW170817, and a 2.6 M⊙ compact star implied by the secondary component of GW190814, a new effective interaction is constructed so as to reproduce the saturation condition of nuclear matter and the ground-state properties of finite, closed-shell nuclei. We find that the neutron star EoS exhibits the rapid stiffening around twice the nuclear saturation density, which is caused by the soft nuclear symmetry energy, Esym. It is also noticeable that the thick Rskin from the PREX-2 experiment can be achieved with the small slope parameter of Esym stemming from the isoscalar-meson mixing. Thus, we speculate that the secondary component of GW190814 is the heaviest neutron star ever discovered. 

Comments: 	8 pages, 5 figures, 2 tables
Subjects: 	Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
Cite as: 	arXiv:2209.02861 [nucl-th]