Bounds on Long-lived Dark Matter Mediators from Neutron Stars

TL;DR

This paper investigates how observations of neutron stars near the Galactic center can set bounds on heavy dark matter models with long-lived mediators decaying into neutrinos, complementing terrestrial searches.

Contribution

It introduces new bounds on heavy dark matter with long-lived mediators using neutrino observations, extending the accessible parameter space.

Findings

Neutrino observatories can constrain dark matter models with long-lived mediators.

Current bounds are complementary to terrestrial dark matter searches.

Future observations will improve sensitivity to these models.

Abstract

Neutron stars close to the Galactic center are expected to swim in a dense background of dark matter. For models in which the dark matter has efficient interactions with neutrons, they are expected to accumulate their own local cloud of dark matter, making them appealing targets for observations seeking signs of dark matter annihilation. For theories with very light mediators, the dark matter may annihilate into pairs of mediators which are sufficiently long-lived to escape the star and decay outside it into neutrinos. We examine the bounds on the parameter space of heavy ($\sim$TeV to $\sim$PeV) dark matter theories with long-lived mediators decaying into neutrinos based on observations of high energy neutrino observatories, and make projections for the future. We find that these observations provide information that is complementary to terrestrial searches, and probe otherwise inaccessible regimes of dark matter parameter space.