Neutron star matter with strange interactions within constraints by GW170817 in a relativistic quark model

Abstract

The effect of strange interactions in neutron star matter and the role of the strange meson-hyperon couplings are studied in a relativistic quark model where the confining interaction for quarks inside a baryon is represented by a phenomenological average potential in an equally mixed scalar-vector harmonic form. The hadron-hadron interaction in nuclear matter is then realized by introducing additional quark couplings to $\ensuremath{\sigma}, \ensuremath{\omega}, \ensuremath{\rho}, {\ensuremath{\sigma}}^{*}$, and $\ensuremath{\phi}$ mesons through mean-field approximations. The meson-baryon couplings are fixed through the SU(6) spin-flavor symmetry and the SU(3) flavor symmetry to determine the hadronic equation of state (EoS). We find that the SU(3) coupling set gives the potential depth between ${\mathrm{\ensuremath{\Lambda}}}^{\ensuremath{'}}\mathrm{s}$ around $\ensuremath{-}5$ MeV and favors a stiffer EoS. Using the stiffest EoS from the SU(3) we determine the tidal Love number ${k}_{2}$, the tidal deformability $\ensuremath{\lambda}$, and the dimensionless tidal deformability ${\mathrm{\ensuremath{\Lambda}}}_{D}$. We obtain a value of ${\mathrm{\ensuremath{\Lambda}}}_{D}=483$ corresponding to a $1.4{M}_{\ensuremath{\bigodot}}$ star while the weighted tidal deformability $\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{\mathrm{\ensuremath{\Lambda}}}=624$ for a symmetric binary system of chirp mass $\mathcal{M}=1.188{M}_{\ensuremath{\bigodot}}$. The radius for the canonical neutron star is found to be 13.1 km.