Massive $\Delta$-resonance admixed hypernuclear stars with anti-kaon condensations

TL;DR

This study explores how (anti)kaon condensations and $\Delta$-resonances affect the structure and maximum mass of hypernuclear stars, revealing that these condensates soften the equation of state and lower star masses.

Contribution

It introduces a covariant density functional model incorporating (anti)kaon and $\Delta$-resonance effects, calibrated with experimental data, to analyze their impact on compact star properties.

Findings

(Anti)kaon condensation softens the equation of state.

Condensation occurs via second-order phase transition without mixed phases.

High potentials lead to extinction of certain hyperons.

Abstract

In this work, we study the effect of (anti)kaon condensation on the properties of compact stars that develop hypernuclear cores with and without an admixture of $\Delta$-resonances. We work within the covariant density functional theory with the parameters adjusted to $K$-atomic and kaon-nucleon scattering data in the kaonic sector. The density-dependent parameters in the hyperonic sector are adjusted to the data on $\Lambda$ and $\Xi^-$ hypernuclei data. The $\Delta$-resonance couplings are tuned to the data obtained from their scattering off nuclei and heavy-ion collision experiments. We find that (anti)kaon condensate leads to a softening of the equation of state and lower maximum masses of compact stars than in the absence of the condensate. Both the $K^-$ and $\bar K^0$-condensations occur through a second-order phase transition, which implies no mixed-phase formation. For large values of (anti)kaon and $\Delta$-resonance potentials in symmetric nuclear matter, we observe that condensation leads to an extinction of $ \Xi^{-,0}$ hyperons. We also investigate the influence of inclusion of additional hidden-strangeness $\sigma^{*}$ meson in the functional and find that it leads to a substantial softening of the equation of state and delay in the onset of (anti)kaons.