Confronting Strange Stars with Compact-Star Observations and New Physics

Abstract

Strange stars ought to exist in the universe according to the strange quark matter hypothesis, which states that matter made of roughly equal numbers of up, down, and strange quarks could be the true ground state of baryonic matter rather than ordinary atomic nuclei. Theoretical models of strange quark matter, such as the standard MIT bag model, the density-dependent quark mass model, or the quasi-particle model, however, appear to be unable to reproduce some of the properties (masses, radii, and tidal deformabilities) of recently observed compact stars. This is different if alternative gravity theory (e.g., non-Newtonian gravity) or dark matter (e.g., mirror dark matter) are considered, which resolve these issues. The possible existence of strange stars could thus provide a clue to new physics, as discussed in this review.

Exploring the Distribution and Impact of Bosonic Dark Matter in Neutron Stars

“…Our utilized DD2 EoS is a specific parameterization for the density-dependent meson couplings in a generalized relativistic density functional (GRDF) for nuclear matter, which consider σ, ω and ρ mesons as exchange particles for describing the effective in-medium interaction of nucleons [71]. Due to the unknown structure of DM-admixed NSs, various nuclear matter EoSs including the ones with phase transition, strange quark matter and hyperonic degrees of freedom have been proposed to be considered in the mixed compact objects [72][73][74][75][76][77][78][79].…”