Kaon-meson condensation and $\Delta$ resonance in hyperonic stellar matter within a relativistic mean-field model

TL;DR

This paper investigates the effects of including $$Delta$\u0000$ resonances and kaon meson condensation in the equation of state of dense hyperonic matter within a relativistic mean-field model, impacting neutron star properties.

Contribution

It introduces the inclusion of $$Delta$\u0000$ resonances into the hyperonic star model and analyzes their influence on the equation of state and neutron star stability.

Findings

$$Delta$\u0000$ resonances soften the equation of state at low densities.

The presence of $$Delta$\u0000$ resonances aligns model predictions with GW170817 observations.

Maximum neutron star mass exceeds 2$M_{\odot}$ with $$Delta$\u0000$ inclusion.

Abstract

We study the equation of state of dense baryon matter within the relativistic mean-field model, and we include ${\Delta}$(1232) isobars into IUFSU model with hyperons and consider the possibility of kaon meson condensation. We find that it is necessary to consider the $\Delta$ resonance state inside the massive neutron star. The critical density of Kaon mesons and hyperons is shifted to a higher density region, in this respect an early appearance of $\Delta$ resonances is crucial to guarantee the stability of the branch of hyperonized star with the difference of the coupling parameter $x_{\sigma \Delta}$ constrained based on the QCD rules in nuclear matter. The $\Delta$ resonance produces a softer equation of state in the low density region, which makes the tidal deformability and radius consistent with the observation of GW170817. As the addition of new degrees of freedom will lead to a softening of the equation of state, the ${\sigma}$-cut scheme, which states the decrease of neutron star mass can be lowered if one assumes a limited decrease of the ${\sigma}$-meson strength at ${\rho_B}$($\rho_B > \rho_0$), finally we get a maximum mass neutron star with $\Delta$ resonance heavier than 2$M_{\odot}$.