Heating neutron stars with inelastic dark matter and relativistic targets

The dense environment of neutron stars makes them an excellent target for probing dark matter interactions with the Standard Model. We study neutron star heating from capture of inelastic dark matter, which can evade direct detection constraints. We investigate kinematics of the inelastic scattering process between quasirelativistic dark matter particles and ultrarelativistic targets in neutron stars, and derive analytical expressions for the maximal mass gap allowed for the scattering to occur. We implement them into a fully relativistic formalism for calculating the capture rate and apply it to various scenarios of inelastic dark matter. The projected constraints from neutron stars can systematically surpass those from terrestrial searches, including direct detection and collider experiments. Neutron stars can also be sensitive to the parameter space of inelastic self-interacting dark matter. Our results indicate that extreme astrophysical environments, such as neutron stars, are an important target for searching dark matter.

Automated summary

Neutron stars' dense environment makes them an excellent target for studying dark matter interactions with the Standard Model. This study investigates the heating of neutron stars caused by the capture of inelastic dark matter, which avoids direct detection constraints. It derives analytical expressions for the maximal mass gap allowed for the scattering process and applies them to calculate the capture rate in neutron stars. The constraints from neutron stars can exceed those from terrestrial searches, including direct detection and collider experiments, making them an important target for exploring dark matter.