Sommerfeld-enhanced annihilation in dark matter substructure: Consequences for constraints on cosmic-ray excesses

Tracy R. Slatyer, Natalia Toro, Neal Weiner

    Research output: Contribution to journalArticle

    Abstract

    In models of dark matter (DM) with Sommerfeld-enhanced annihilation, where the annihilation rate scales as the inverse velocity, N-body simulations of DM structure formation suggest that the local annihilation signal may be dominated by small, dense, cold subhalos. This contrasts with the usual assumption of a signal originating from the smooth DM halo, with much higher velocity dispersion. Accounting for local substructure modifies the parameter space for which Sommerfeld-enhanced annihilating DM can explain the PAMELA and Fermi excesses. Limits from the inner galaxy and the cosmic microwave background are weakened, without introducing new tension with substructure-dependent limits, such as from dwarf galaxies or isotropic gamma-ray studies. With substructure, previously excluded parameter regions with mediators of mass ∼1-200MeV are now easily allowed. For O(MeV) mediators, subhalos in a specific range of host halo masses may be evaporated, further suppressing diffuse signals without affecting substructure in the Milky Way.

    Original languageEnglish (US)
    Article number083534
    JournalPhysical Review D - Particles, Fields, Gravitation and Cosmology
    Volume86
    Issue number8
    DOIs
    StatePublished - Oct 22 2012

    ASJC Scopus subject areas

    • Nuclear and High Energy Physics
    • Physics and Astronomy (miscellaneous)

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