Influence of the nuclear symmetry energy slope on observables of compact stars with Δ -admixed hypernuclear matter

Abstract

In this work, we study the effects of the nuclear symmetry energy slope on the neutron star dense matter equation of state and its impact on neutron star observables (mass-radius, tidal response). We construct the equation of state within the framework of covariant density functional theory implementing coupling schemes of nonlinear and density-dependent models with viability of heavier non-nucleonic degrees of freedom. The slope of the symmetry energy parameter $({L}_{\text{sym}})$ is adjusted following the density dependence of isovector meson coupling to baryons. We find that smaller values of ${L}_{\text{sym}}$ at saturation favor early appearance of $\mathrm{\ensuremath{\Delta}}$ resonances in comparison to hyperons, leading to latter's threshold at higher matter densities. We also investigate the dependence of ${L}_{\text{sym}}$ on tidal deformability and the compactness parameter of a $1.4{M}_{\ensuremath{\bigodot}}$ neutron star for different equations of state and observe similar converging behavior for larger ${L}_{\text{sym}}$ values.