Robust Gamma Ray Signature of WIMP Dark Matter

TL;DR

This paper predicts a distinctive gamma ray signature from WIMP dark matter annihilation, specifically a sharp edge in the spectrum that could confirm WIMP properties if observed by gamma ray telescopes.

Contribution

It provides a model-independent prediction of the gamma ray spectrum from WIMP annihilation, highlighting a unique spectral feature for detection.

Findings

Sharp edge feature in gamma ray spectrum at WIMP mass

Prediction is robust across different WIMP models

Potential for detection with current gamma ray telescopes

Abstract

If dark matter consists of weakly interacting massive particles (WIMPs), annihilation of WIMPs in the galactic center may lead to an observable enhancement of high energy gamma ray fluxes. We predict the shape and normalization of the component of the flux due to final state radiation by charged particles produced in WIMP annihilation events. The prediction is made without any assumptions about the microscopic theory responsible for WIMPs, and depends only mildly on the unknown distribution of the total WIMP annihilation cross section among the possible final states. In particular, if the WIMPs annihilate into a pair of charged fermions (leptons or quarks), the photon spectrum possesses a sharp edge feature, dropping abruptly at a photon energy equal to the WIMP mass. If such a feature is observed, it would provide strong evidence for the WIMP-related nature of the flux enhancement, as well as a measurement of the WIMP mass. We discuss the prospects for observational discovery of this feature at ground-based and space-based gamma ray telescopes.