Substructure, Sommerfeld, and CR Signals

          @misc{ pirsa_PIRSA:11090092,
            doi = {10.48660/11090092},
            url = {https://pirsa.org/11090092},
            author = {Slatyer, Tracy},
            keywords = {Particle Physics},
            language = {en},
            title = {Substructure, Sommerfeld, and CR Signals},
            publisher = {Perimeter Institute},
            year = {2011},
            month = {sep},
            note = {PIRSA:11090092 see, \url{https://pirsa.org}}
          }
          

Abstract

Models of dark matter with Sommerfeld-enhanced annihilation have been proposed to explain the CR excess observed by the PAMELA and Fermi experiments. In such models, the local annihilation signal can easily be dominated by small, dense, cold subhalos, instead of by the smooth DM halo as usually assumed. I will discuss how such a "substructure+Sommerfeld" scenario modifies constraints from the CMB, limits on DM self-interaction, and bounds from measurements of inner-Galaxy gamma rays and the extragalactic diffuse background. These constraints provide stringent limits on the usual smooth-halo scenario, robustly ruling out force carrier masses below ~200 MeV (in the context of explaining the PAMELA/Fermi signals) and causing tension for higher mediator masses, but in the presence of a modest amount of local substructure, force carrier masses down to 20 MeV or even lower can still be consistent with these bounds.