Hybrid stars with hyperons: structure based on QCD sum rule coupling constants

Abstract

We present a comprehensive study of hybrid stars composed of hadrons, leptons, and quarks within a relativistic mean-field framework. Using coupling constants derived from QCD sum rules (QCDSR), we first determine the bulk properties of nuclear matter and evaluate the single-particle potentials of nucleons and hyperons to constrain the hadronic sector. The equation of state (EOS) under beta equilibrium is then constructed employing the $\ddot{I}ƒ-\ddot{I}‰-\ddot{I}$ model for the hadronic phase, while the quark phase is described using both the MIT bag model and the Nambu-Jona-Lasinio (NJL) model. The hadron-quark phase transition is analyzed through both Gibbs and Maxwell constructions. Based on resulting EOSs, we obtain the mass-radius relations of hybrid stars, investigate particle fractions and their radial distributions, and calculate the tidal Love number (${\mathcal{K}}_2$) and the dimensionless tidal deformability ($\Lambda$). Our results provide quantitative predictions relevant for comparison with current multimessenger astrophysical observations.

25 pages, 6 figures, 4 tables