On the Impact of Dark Matter Scattering on the Trajectory of High-Energy Cosmic Rays

TL;DR

This paper investigates how scattering off dark matter can significantly deflect high-energy cosmic rays, potentially affecting their observed trajectories and providing insights into dark matter interactions.

Contribution

It provides a detailed calculation of cosmic-ray deflections due to dark matter scattering, considering various energies and interaction strengths, highlighting observable effects.

Findings

Deflection angles are largely independent of dark matter mass.

Large interaction cross sections can cause deflections exceeding observatory resolution.

Predicted deflections are significant at low cosmic-ray energies with strong interactions.

Abstract

We study the impact on the trajectory of high-energy cosmic-ray protons of scattering off the cosmic dark matter. We compute the scattering angle as a function of the cosmic-ray energy, of the dark matter mass, and of the interaction strength for a few representative choices for the relevant interaction cross section. We find that the typical deflection angle over the cosmic ray path is largely independent of the dark matter mass. Given existing limits on the interaction strength, we compute the average deflection angle. We find that for large interaction cross sections and low cosmic ray energies, the predicted deflection angle is much larger than the angular resolution of very high-energy cosmic-ray observatories such as Pierre Auger.