Mahbubeh Shahrbaf (IFT)

Hyperons, baryons containing strange quarks, are abundantly produced and studied in high-energy heavy-ion experiments such as HADES (GSI), ALICE (CERN), STAR (RHIC), and NA61/SHINE (CERN). These experiments provide essential constraints on hyperon–nucleon and hyperon–hyperon interactions, offering a bridge between nuclear physics and astrophysics. Under the extreme densities realized in neutron star (NS) interiors, hyperons are also expected to emerge, yet their actual presence remains one of the most fundamental open questions in the study of dense matter. Understanding their role is key to constraining the equation of state (EOS) of strongly interacting matter and linking terrestrial measurements to astrophysical observations. In this talk, I will present a microscopic analysis of hyperonic matter based on the lowest-order constrained variational (LOCV) method extended to include interacting Λ hyperons. Using realistic spin- and parity-dependent Λ–N and Λ–Λ potentials constrained by hypernuclear data, I will discuss the resulting EOS, composition, sound speed, and the macroscopic properties of NSs. The inclusion of Λ hyperons leads to a moderate softening of the EOS, reducing the maximum NS mass while preserving consistency with current observational constraints from NICER and gravitational wave measurements. Our results indicate that Λ hyperons can exist in NS cores across the observed mass range without conflicting with these constraints. In the final part of the talk, I will turn to a relativistic mean-field (RMF) framework, the DD2Y-T model, to illustrate how such approaches incorporate hyperonic degrees of freedom and how the possible inclusion of bosonic dark matter candidates (sexaquarks) can further modify the hyperonic EOS. This combined study of hyperons and dark matter within hybrid models highlights how these two strangeness-bearing degrees of freedom may jointly influence the internal composition and observable properties of NSs.