Search for Dark Matter with GLAST

TL;DR

The paper addresses detecting dark matter through gamma rays produced by neutralino annihilation in the Milky Way halo, motivated by the GeV excess observed by EGRET. It develops the framework for indirect detection in the MSSM, describing the gamma-ray flux as φγ ∝ (σv/mχ^2)∫ρ^2 dl, which factorizes into a particle-physics term and a halo J-factor J(ψ). It then analyzes the Gamma-ray Large Area Telescope GLAST, detailing its design, capabilities, and projected sensitivity to diffuse and point-source gamma-ray emission, and discusses how GLAST complements cosmic-ray experiments like PAMELA and AMS. The work argues that GLAST, together with halo-models and multi-frequency data, can probe cosmologically relevant regions of parameter space and potentially detect neutralino-induced signals before the LHC era, marking a significant step in indirect dark matter searches.

Abstract

The detection of exotic cosmic rays due to pair annihilation of dark matter particles in the Milky Way halo is a viable techniques to search for supersymmetric dark matter candidates. The study of the spectrum of gamma-rays, antiprotons and positrons offers good possibilities to perform this search in a significant portion of the Minimal Supersymmetric Standard Model parameter space. In particular the EGRET team have seen a convincing signal for a strong excess of emission from the Galactic center that has no simple explanation with standard processes. We will review the limits achievable with the experiment GLAST taking into accounts the LEP results and we will compare this method with the antiproton and positrons experiments.

Figures (9)

• Figure 1: Gamma-ray energy spectrum of the inner galaxy ($300^\circ \ge l \le 30^\circ$) compared with what is expected for standard propagation models
• Figure 2: Gamma-ray energy spectrum of the inner galaxy ($300^\circ \ge l \le 30^\circ$) compared with what is expected for standard propagation models
• Figure 3: The GLAST instrument, exploded to show the detector layers in a tower, the stacking of the CsI logs in the calorimeter, and the integration of the subsystems.
• Figure 4: Total photon spectrum from the galactic center from standard propagation models and from one neutralino annihilation models and the kind of statistical errors that it is expected in three years with GLAST.
• Figure 5: GLAST effective area as a function of energy including all background and track quality cuts compared with EGRET's one