Enhanced Gamma Ray Signals in Cosmic Proton-Wimp Collisions Due to Hadronization

In this paper, we investigate the gamma ray signal produced from dark matter collisions with high energy cosmic protons. Notably, we extend past results by including important hadronization effects. Showering and hadronization produces a high multiplicity of photons from the decays of hadrons, whose rate is not suppressed by the fine structure constant. Notably, proton remnants that do not participate in hard scattering, can produce a large rate of photons in the forward direction. These effects significantly enhance the photon rate and alter the energy and angular distributions compared to previous results which used only parton level calculations. Due to this modification, the gamma ray signal from the nearby active galactic nuclei Centaurus A is potentially testable in future Fermi-LAT and HESS measurements, for a dark matter mass and coupling consistent with current XENON100 bounds.