Speaker
Description
We investigate the equation of state (EOS) and macroscopic properties of neutron stars (NSs) and hyperonic stars within the framework of the lowest order constrained variational (LOCV) method, extended to include interacting Λ hyperons. The ΛN and ΛΛ interactions are described by realistic spin- and parity-dependent potentials fitted to hypernuclear data. Cold, charge-neutral, and β-equilibrated matter composed of neutrons, protons, electrons, muons, and Λ hyperons is considered. We compute particle fractions, chemical potentials, the EOS, speed of sound, tidal deformability, and stellar structure by solving the Tolman-Oppenheimer-Volkoff equations, and compare our results with recent NICER and gravitational-wave observations. The inclusion of Λ hyperons leads to EOS softening, reducing the maximum NS mass while keeping it consistent with the 2 solar mass constraint. At 1.4 solar mass, the model satisfies observational limits on radius and tidal deformability, with the Λ onset occurring below this mass permitting even canonical-mass NSs to accommodate hyperons. These results suggest that hyperons can appear in NSs across the observed mass range without violating current astrophysical constraints, and that the extended LOCV method provides a consistent, microscopic approach to modeling dense hypernuclear matter.
