Abstract
Dark matter with Sommerfeld-enhanced annihilation has been proposed to explain observed cosmic ray positron excesses in the 10 GeV to TeV energy range. We show that the required enhancement implies thermal relic densities that are too small to be all of dark matter. We also show that the dark matter is sufficiently self-interacting that observations of elliptical galactic dark matter halos exclude large Sommerfeld enhancement for light force carriers. Resonant Sommerfeld enhancement does not modify these conclusions, and the astrophysical boosts required to resolve these discrepancies are disfavored, especially when significant self-interactions suppress halo substructure.
- Received 15 December 2009
DOI:https://doi.org/10.1103/PhysRevLett.104.151301
©2010 American Physical Society
Synopsis
Trouble for dark matter explanations of excess cosmic positrons
Published 16 April 2010
Theories of dark matter interacting with a light force carrier, proposed to explain the excess of high-energy positrons in the cosmic rays, turn out to have problems.
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