Confronting strange stars with compact-star observations and new physics

TL;DR

This review explores how strange stars, if they exist, could reveal new physics by comparing observational data with theoretical models and considering alternative gravity theories and dark matter.

Contribution

It discusses the potential of strange stars to serve as probes for new physics and evaluates how alternative theories can reconcile models with observations.

Findings

Standard models struggle to match observed star properties.

Alternative gravity and dark matter models improve model-data agreement.

Strange stars could be key to discovering 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.