A dark matter model that reconciles tensions between the cosmic-ray $e^\pm$ excess and the gamma-ray and CMB constraints

Understand

The cosmic-ray (CR) $e^\pm$ excess observed by AMS-02 can be explained by dark matter (DM) annihilation.

• However, the DM explanation requires a large annihilation cross section which is strongly disfavored by other observations, such as the Fermi-LAT gamma-ray observation of dwarf galaxies and the Planck observation of the cosmic microwave background (CMB).
• Moreover, the DM annihilation cross section required by the CR $e^\pm$ excess is also too large to generate the correct DM relic density with thermal production.
• In this work we use the Breit-Wigner mechanism with a velocity dependent DM annihilation cross section to reconcile these tensions.