Neutron Star Constraints on Neutron Dark Decays

• DOI: 10.3390/universe9110484
• Publication Date: 2023-11-17T15:10:06Z
• Authors: Dake Zhou
• Keywords: neutron lifetime; 0103 physical sciences; Elementary particle physics; QC793-793.5; neutron star; 01 natural sciences; dark matter

Motivated by the neutron lifetime puzzle, it is proposed that neutrons may decay into new states yet to be observed. We review the neutron star constraints on dark fermions carrying unit baryon number with masses around 939 MeV, and discuss the interaction strengths required for the new particle. The possibility of neutrons decaying into three dark fermions is investigated. While up to six flavors of dark quarks with masses around 313 MeV can be compatible with massive pulsars, any such exotic states lighter than about 270 MeV are excluded by the existence of low-mass neutron stars around ∼1.2M⊙. Light dark quarks in the allowed mass range may form a halo surrounding normal neutron stars. We discuss the potential observable signatures of the halo during binary neutron star mergers.