Dark Matter Annihilation and the PAMELA, FERMI and ATIC Anomalies

TL;DR

This paper investigates whether dark matter annihilation can explain cosmic ray anomalies observed by PAMELA, FERMI, and ATIC, and explores non-standard cosmological models to reconcile large annihilation cross sections with observed relic abundances.

Contribution

It proposes non-standard cosmological scenarios that allow large dark matter annihilation cross sections without conflicting with relic abundance observations.

Findings

Non-standard cosmologies can reconcile large annihilation cross sections with relic abundance.

Dark matter annihilation could explain cosmic ray excesses.

Standard models face conflicts with observed relic densities.

Abstract

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.