Dark Resonance

TL;DR

This paper presents models of particle dark matter with a near-threshold resonance that enhances annihilation signals at certain velocities, explaining cosmic ray excesses while satisfying observational constraints.

Contribution

It introduces explicit dark matter models with a resonance mechanism that enhances annihilation at specific velocities and naturally suppresses it at low velocities to meet observational bounds.

Findings

Resonant enhancement explains PAMELA and FERMI cosmic ray excesses.

The model's enhancement shuts off at low velocities, avoiding CMB and gamma-ray constraints.

Provides a new framework for velocity-dependent dark matter annihilation.

Abstract

We construct explicit models of particle dark matter where the attractive force in the dark matter sector creates a narrow near-threshold resonance that qualitatively changes the energy dependence of the annihilation cross section. In these models, the resonant enhancement of the dark matter annihilation can easily source the excess of energetic leptons observed by experiments on PAMELA and FERMI satellites. The distinct feature of these models is that by construction the enhancement of the annihilation cross section shuts off when the dark matter velocity falls below the typical Milky Way values, thus automatically satisfying constraints on dark matter annihilation imposed by the CMB anisotropies and gamma ray constraints from satellite galaxies.