The WIMP Forest: Indirect Detection of a Chiral Square

TL;DR

This paper explores how WIMP annihilation in a model with two universal extra dimensions produces a distinctive gamma-ray spectrum with multiple lines, potentially observable by the Fermi Telescope, revealing details of the dark sector.

Contribution

It introduces the concept of a WIMP forest of gamma-ray lines from a specific extra-dimensional dark matter model, highlighting its detectability.

Findings

A series of gamma-ray lines (WIMP forest) can arise from WIMP annihilation.

The spectrum features a distinctive 2-bump plus continuum shape.

Potential observability with current gamma-ray telescopes like Fermi.

Abstract

The spectrum of photons arising from WIMP annihilation carries a detailed imprint of the structure of the dark sector. In particular, loop-level annihilations into a photon and another boson can in principle lead to a series of lines (a WIMP forest) at energies up to the WIMP mass. A specific model which illustrates this feature nicely is a theory of two universal extra dimensions compactified on a chiral square. Aside from the continuum emission, which is a generic prediction of most dark matter candidates, we find a "forest" of prominent annihilation lines that, after convolution with the angular resolution of current experiments, leads to a distinctive (2-bump plus continuum) spectrum, which may be visible in the near future with the Fermi Gamma-Ray Space Telescope (formerly known as GLAST).