Exclusion of canonical WIMPs by the joint analysis of Milky Way dwarfs with Fermi

TL;DR

This paper sets new constraints on the properties of WIMP dark matter particles by analyzing gamma-ray data from seven Milky Way dwarf galaxies, excluding certain WIMP masses and annihilation channels.

Contribution

It provides the first joint analysis of multiple dwarf galaxies using Fermi data with a frequentist approach to constrain WIMP annihilation cross sections.

Findings

Excludes WIMPs <40 GeV annihilating into b-bbar.

Mass limits vary from 19 GeV to 240 GeV depending on systematics.

Constraints are robust within 95% systematic errors.

Abstract

Dwarf spheroidal galaxies are known to be excellent targets for the detection of annihilating dark matter. We present new limits on the annihilation cross section of Weakly Interacting Massive Particles (WIMPs) based on the joint analysis of seven Milky Way dwarfs using a frequentist Neyman construction and Pass 7 data from the Fermi Gamma-ray Space Telescope. We exclude generic WIMP candidates annihilating into b-bbar with mass less than 40 GeV that reproduce the observed relic abundance. To within 95% systematic errors on the dark matter distribution within the dwarfs, the mass lower limit can be as low as 19 GeV or as high as 240 GeV. For annihilation into tau+tau- these limits become 19 GeV, 13 GeV, and 80 GeV respectively.