# Dark Kinetic Heating of Neutron Stars and An Infrared Window On WIMPs, SIMPs, and Pure Higgsinos

## TL;DR

This paper proposes a model-independent method to detect dark matter by observing infrared and optical emissions from neutron stars heated by dark matter particles, offering new detection avenues for various dark matter types.

## Contribution

It introduces a novel, largely model-independent signature of dark matter interactions with neutron stars, enabling detection of diverse dark matter candidates including inelastic types like Higgsinos.

## Key findings

- Neutron star heating can reveal dark matter-nucleon cross-sections above 2×10⁻⁴⁵ cm².
- Infrared and optical emissions from neutron stars serve as potential dark matter signals.
- Sensitivity varies with dark matter mass, improving detection prospects with telescope exposure.

## Abstract

We identify a largely model-independent signature of dark matter interactions with nucleons and electrons. Dark matter in the local galactic halo, gravitationally accelerated to over half the speed of light, scatters against and deposits kinetic energy into neutron stars, heating them to infrared blackbody temperatures. The resulting radiation could potentially be detected by the James Webb Space Telescope, the Thirty Meter Telescope, or the European Extremely Large Telescope. This mechanism also produces optical emission from neutron stars in the galactic bulge, and X-ray emission near the galactic center, because dark matter is denser in these regions. For GeV - PeV mass dark matter, dark kinetic heating would initially unmask any spin-independent or spin-dependent dark matter-nucleon cross-sections exceeding $2 \times 10^{-45}$ cm$^2$, with improved sensitivity after more telescope exposure. For lighter-than-GeV dark matter, cross-section sensitivity scales inversely with dark matter mass because of Pauli blocking; for heavier-than-PeV dark matter, it scales linearly with mass as a result of needing multiple scatters for capture. Future observations of dark sector-warmed neutron stars could determine whether dark matter annihilates in or only kinetically heats neutron stars. Because inelastic inter-state transitions of up to a few GeV would occur in relativistic scattering against nucleons, elusive inelastic dark matter like pure Higgsinos can also be discovered.