Producing the GeV Galactic Center Excess via Cosmic Ray-Dark Matter Scattering with Debopam Goswami

The Fermi Large Area Telescope (Fermi-LAT) has observed a gamma-ray excess from the Galactic Center (GC) with the energy spectrum peaked around∼2 GeV, commonly referred to as the Galactic Center GeV Excess (GCE). This excess has been persistent for 17 years, with possible explanations including dark matter (DM) annihilation and unresolved millisecond pulsars. In this pursuit to explain GCE, we propose a novel mechanism for generating gamma rays from the GC via scattering of cosmic rays off sub-GeV DM in the Milky Way halo. In this analysis, we investigate two DM models: (a) an inelastic DM model where the lighterDM is up-scattered to a heavier DM, followed by its subsequent decay producing photons in the final state, and (b) an elastic DM model producing photons in the final state via a 2 →3 scattering process. The fits to the observed GCE spectrum obtained from this framework for a range of viable model parameters are comparable to those from DM annihilation and millisecond pulsar solutions in the literature.

This lecture was made possible by the William C. Ferguson Fund.