Constraining hyperonic relativistic mean-field models with rapidly rotating neutron stars

Abstract

Motivated by the recent mass measurement of the black-widow pulsar PSR~J0952$-$0607 with $M=2.35\pm 0.11M_{\odot }$, we investigate how the masses of heavy, rapidly rotating millisecond pulsars can be used to constrain relativistic mean-field (RMF) models containing hyperonic degrees of freedom. In our approach, hyperons are incorporated following the spin-flavor SU(6) symmetry scheme for the vector-meson couplings. We find that increasing the nonlinear $\omega$-meson vector self-coupling parameter $\zeta$ suppresses the hyperon fraction and can alter the onset ordering of the ${\Sigma }^{-}$ and ${\Xi }^{-}$ hyperons. By computing rotating neutron-star configurations at the observed spin frequency $707\mathrm{Hz}$ of PSR~J0952$-$0607, we identify RMF models compatible with this pulsar's observed lower-mass bound. Using an empirical relation for the maximum neutron star mass, the PSR~J0952$-$0607 observational contraint is mapped onto the allowed RMF parameter space in $n_0$, $m^{\ast }$, and $\zeta$.

Comments: 19 pages, 12 figures