probing hidden sectors using neutron star phase transitions

You can find further details of this work here: Bhutani, Raj & Zuraiq, Phys.Rev.D 113 10, 103046, 2026

The interiors of neutron stars (NSs) are extremely dense. In fact, they are dense enough that they are ideal sites for a deconfinement phase transition, leading to the conversion of hadronic matter to quarks. Due to the highly uncertain nature of high density matter and the exact dense matter equation of state (EoS), it is unclear what mechanism triggers these phase transitions. In fact, in certain models, the potential barrier for the nucleation of quark matter droplets may be high enough that astrophysical mechanisms won’t do.

An energy injection from hidden sector states could trigger a phase transition within NSs, leading to catastrophic rearrangement of its structure, and the production of energetic gamma rays or the collapse of the NS to a black hole. The observed rates of such events allow us to set limits on particle dark matter properties based on the exact energy deposition mechanism, i.e., scattering, decay, or annihilation; the decay of the neutron into exotic channels; and the decay of the proton.

Using the observed existence of ancient neutron stars and estimates of the GRB rate, we then set some of the strictest (albeit conditional) limits on dark matter scatters, annihilations, and decays that are tens of orders stronger than those from terrestrial searches. For smaller energy barriers, lower limits on nucleon decay lifetimes of the order of 10^64 yr may be obtained.