Enhancement of Dark Matter Annihilation via Breit-Wigner Resonance

TL;DR

This paper demonstrates how Breit-Wigner resonance can significantly enhance dark matter annihilation rates, potentially explaining recent cosmic ray anomalies and aiding in dark matter model development.

Contribution

It explicitly analyzes the evolution of Breit-Wigner enhanced annihilation cross sections and their implications for dark matter relic density and cosmic ray anomalies.

Findings

Breit-Wigner enhancement can produce large boost factors near narrow resonances.

Both physical and unphysical pole cases can explain cosmic ray anomalies.

Calculated annihilation couplings assist in dark matter model building.

Abstract

The Breit-Wigner enhancement of the thermally averaged annihilation cross section <\sigma v> is shown to provide a large boost factor when the dark matter annihilation process nears a narrow resonance. We explicitly demonstrate the evolution behavior of the Breit-Wigner enhanced <\sigma v> as the function of universe temperature for both the physical and unphysical pole cases. It is found that both of the cases can lead an enough large boost factor to explain the recent PAMELA, ATIC and PPB-BETS anomalies. We also calculate the coupling of annihilation process, which is useful for an appropriate model building to give the desired dark matter relic density.