Neutron Star Internal Heating Constraints on Mirror Matter

Mirror sectors have been proposed to address the problems of dark matter, baryogenesis, and the neutron lifetime anomaly. In this work we study a new, powerful probe of mirror neutrons: neutron star temperatures. When neutrons in the neutron star core convert to mirror neutrons during collisions, the vacancies left behind in the nucleon Fermi seas are refilled by more energetic nucleons, releasing immense amounts of heat in the process. We derive a new constraint on the allowed strength of neutron-mirrorneutron mixing from observations of the coldest (sub-40 000 Kelvin) neutron star, PSR 2144 - 3933. Our limits compete with laboratory searches for neutron-mirror-neutron transitions but apply to a range of mass splittings between the neutron and mirror neutron that is 19 orders of magnitude larger. This heating mechanism, also pertinent to other neutron disappearance channels such as exotic neutron decay, provides a compelling physics target for upcoming ultraviolet, optical, and infrared telescopes to study thermal emissions of cold neutron stars.

Automated summary

Mirror sectors offer a new approach to investigating neutron-mirror neutron interactions, with neutron star temperatures serving as a powerful probe. The heating mechanism caused by the conversion of neutrons to mirror neutrons in neutron stars provides constraints on the strength of neutron-mirror-neutron mixing and offers a promising target for future telescope observations.