Fermi LAT Search for Dark Matter in Gamma-ray Lines and the Inclusive Photon Spectrum

TL;DR

This paper reports on Fermi LAT's search for gamma-ray lines and diffuse background signals from dark matter, setting upper limits on flux, cross sections, and decay lifetimes across a broad energy range based on two years of data.

Contribution

It provides the first comprehensive flux upper limits for gamma-ray lines and diffuse background from dark matter over a wide energy range using Fermi LAT data.

Findings

Set upper limits on gamma-ray spectral lines from 7 to 200 GeV.

Established constraints on dark matter decay lifetimes from 4.8 to 264 GeV.

Provided cross section limits for dark matter annihilation models.

Abstract

Dark matter particle annihilation or decay can produce monochromatic gamma-ray lines and contribute to the diffuse gamma-ray background. Flux upper limits are presented for gamma-ray spectral lines from 7 to 200 GeV and for the diffuse gamma-ray background from 4.8 GeV to 264 GeV obtained from two years of Fermi Large Area Telescope data integrated over most of the sky. We give cross section upper limits and decay lifetime lower limits for dark matter models that produce gamma-ray lines or contribute to the diffuse spectrum, including models proposed as explanations of the PAMELA and Fermi cosmic-ray data.