Elastic and Inelastic Scattering of Cosmic-Rays on Sub-GeV Dark Matter

Understand

We revisit the signatures from collisions of cosmic-rays on sub-GeV dark matter (DM) in the Milky Way.

• In addition to the upscattered DM component that can be probed by existing DM and neutrino experiments widely discussed, we examine the associated signals in $\gamma$-rays and neutrinos that span a wide energy range due to the inelastic scatterings.
• Assuming a simple vector portal DM model for illustration, we compute both the upscattered DM flux by cosmic-ray protons, and the resulting emission of secondary $\gamma$-rays and high-energy neutrinos from proton excitation, hadronization, and the subsequent meson decay.
• We derive limits on coupling constants in the vector portal model using data from the $\gamma$-ray and high-energy neutrino telescopes including Fermi, H.E.S.S.