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arXiv · 0904.3933

Protohalo Constraints to the Resonant Annihilation of Dark Matter

Francis-Yan Cyr-Racine·Stefano Profumo·Kris Sigurdson
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Abstract

It has recently been argued that the PAMELA, ATIC and PPB-BETS data showing an anomalous excess of high-energy cosmic ray positrons and electrons might be explained by dark matter annihilating in the Galactic halo with a cross section resonantly enhanced compared to its value in the primeval plasma. We find that with a very large annihilation cross section the flash of energetic photons and electron-positron pairs expected from dark-matter annihilation in the first protohalos that form at redshift z~40 is likely substantial and observable. As a consequence, bounds on the allowed energy injection into the primordial gas and the energy density of the diffuse gamma-ray background give rise to limits on the low-velocity dark matter cross section that can be difficult to reconcile with this interpretation of the PAMELA, ATIC and PPB-BETS results.

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Francis-Yan Cyr-Racine, Stefano Profumo, Kris Sigurdson. 2009-05-28. Protohalo Constraints to the Resonant Annihilation of Dark Matter. https://doi.org/10.1103/physrevd.80.081302

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