New Multi-messenger Probe of Dark Matter-Nucleon Interactions from Ultra-high Energy Cosmic Ray Acceleration

TL;DR

This paper proposes that dark matter spikes near supermassive black holes can influence ultra-high-energy cosmic rays, enabling new constraints on dark matter-nucleon interactions through cosmic ray observations.

Contribution

It introduces a novel method to constrain dark matter properties by analyzing the effects of dark matter spikes on cosmic ray composition and survivability.

Findings

Dark matter spikes can fragment heavy nuclei in cosmic rays.

Cosmic ray data exclude certain dark matter-nucleon cross sections.

Constraints are competitive with existing probes in specific mass ranges.

Abstract

It has been suggested that the density of dark matter (DM) halo can be highly enhanced around supermassive black holes at the centers of massive galaxies. If real, these DM \emph{spikes} would offer new opportunities to probe the properties of DM. In this work, we point out that DM spikes can significantly impact the composition and survivability of ultra-high-energy cosmic rays accelerated near supermassive black holes. A large DM-nucleon cross section would fragment heavy nuclei into lighter elements and prevent them from attaining the energies observed at Earth. While the origin of cosmic rays remains a mystery, we show that if the highest-energy cosmic rays on Earth come from sources like NGC 1068, then cross sections of size $\sigma_{\chi p} \leq 10^{-33} \left( \frac{m_\chi}{\mathrm{GeV}}\right)\;\mathrm{cm^{2}}$ would be excluded by cosmic ray data. These bounds can be competitive with other existing probes and rule out new parameter space in the DM mass region $m_\chi\in [3\;\mathrm{MeV}, 30\;\mathrm{MeV}]$. While the uncertainties on the acceleration mechanism of cosmic rays prevent us from setting robust limits, our study highlights an important connection between DM spikes and cosmic ray physics that is complementary to existing cosmological and direct detection constraints.