Massive <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi mathvariant="normal">Δ</mml:mi></mml:math>-resonance admixed hypernuclear stars with antikaon condensations

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 $\mathrm{\ensuremath{\Delta}}$-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 $\mathrm{\ensuremath{\Lambda}}$ and ${\mathrm{\ensuremath{\Xi}}}^{\ensuremath{-}}$ hypernuclei data. The $\mathrm{\ensuremath{\Delta}}$-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 ${K}^{\ensuremath{-}}$ and ${\overline{K}}^{0}$ condensations occur through a second-order phase transition, which implies no mixed-phase formation. For large values of (anti)kaon and $\mathrm{\ensuremath{\Delta}}$-resonance potentials in symmetric nuclear matter, we observe that condensation leads to an extinction of ${\mathrm{\ensuremath{\Xi}}}^{\ensuremath{-},0}$ hyperons. We also investigate the influence of inclusion of additional hidden-strangeness ${\ensuremath{\sigma}}^{*}$ 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.