Dark Matter Annihilation and the PAMELA, FERMI and ATIC Anomalies

Understand

If dark matter (DM) annihilation accounts for the tantalizing excess of cosmic ray electron/positrons, as reported by the PAMELA, ATIC, HESS and FERMI observatories, then the implied annihilation cross section must be relatively large.

• This results, in the context of standard cosmological models, in very small relic DM abundances that are incompatible with astrophysical observations.
• We explore possible resolutions to this apparent conflict in terms of non-standard cosmological scenarios; plausibly allowing for large cross sections, while maintaining relic abundances in accord with current observations.