Constraints on WIMP and Sommerfeld-Enhanced Dark Matter Annihilation from HESS Observations of the Galactic Center

TL;DR

This paper uses HESS telescope observations of the Galactic center to set constraints on WIMP dark matter models, especially those with Sommerfeld enhancement, ruling out many parameter spaces consistent with other astrophysical signals.

Contribution

It provides new gamma-ray observational constraints on WIMP and Sommerfeld-enhanced dark matter annihilation models, surpassing other existing constraints in many cases.

Findings

Constraints on WIMP annihilation into b/b-bar near thermal cross section at ~3 TeV

Tau channel constraints within a factor of ~2 of thermal cross section

Gamma-ray data rules out all models fitting PAMELA and Fermi-LAT signals

Abstract

We examine the constraints on models of weakly interacting massive particle (WIMP) dark matter from the recent observations of the Galactic center by the High Energy Spectroscopic System (HESS) telescope. We analyze canonical WIMP annihilation into Standard Model particle final states, including b/b-bar, t/t-bar and W^+ W^-. The constraints on annihilation into b/b-bar is within an order of magnitude of the thermal cross section at ~3 TeV, while the tau^+/tau^- channel is within a factor of ~2 of thermal. We also study constraints on Sommerfeld-enhanced dark matter annihilation models, and find that the gamma-ray observational constraints here rule out all of the parameter space consistent with dark matter annihilation interpretations of PAMELA and the Fermi-LAT e^+/e^- spectrum, in specific classes of models, and strongly constrains these interpretations in other classes. The gamma-ray constraints we find are more constraining on these models, in many cases, than current relic density, cosmic microwave background, halo shape and naturalness constraints.