Vol 24, No 6

Inelastic Scattering of Dark Matter with Heavy Cosmic Rays

Keyu Lu, Yue-Lin Sming Tsai, Qiang Yuan and Le Zhang


We investigate the impact of inelastic collisions between dark matter (DM) and heavy cosmic ray (CR) nuclei on CR propagation. We approximate the fragmentation cross-sections for DM-CR collisions using collider-measured proton-nuclei scattering cross-sections, allowing us to assess how these collisions affect the spectra of CR boron and carbon. We derive new CR spectra from DM-CR collisions by incorporating their cross-sections into the source terms and solving the diffusion equation for the complete network of reactions involved in generating secondary species. In a specific example with a coupling strength of bχ = 0.1 and a DM mass of mχ = 0.1 GeV, considering a simplified scenario where DM interacts exclusively with oxygen, a notable modification in the boron-to-carbon spectrum due to the DM-CR interaction is observed. Particularly, the peak within the spectrum, spanning from 0.1 to 10 GeV, experiences an enhancement of approximately 1.5 times. However, in a more realistic scenario where DM particles interact with all CRs, this peak can be amplified to twice its original value. Utilizing the latest data from AMS-02 and DAMPE on the boron-to-carbon ratio, we estimate a 95% upper limit for the effective inelastic cross-section of DM-proton as a function of DM mass. Our findings reveal that at mχ ≃ 2 MeV, the effective inelastic cross-section between DM and protons must be less than  .


Key words: elementary particles – nuclear reactions – nucleosynthesis – abundances – scattering – astroparticle physics – (cosmology:) dark matter

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