Hunting dark matter gamma-ray lines with the Fermi LAT

Journal Article · Sun May 01 04:00:00 EDT 2011 · Journal of Cosmology and Astroparticle Physics

DOI:https://doi.org/10.1088/1475-7516/2011/05/027· OSTI ID:22277691

Vertongen, Gilles ^[1]; Weniger, Christoph ^[2]

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1. Deutsches Elektronen-Synchrotron (DESY), Notkestrasse 85, 22603 Hamburg (Germany)
2. Max-Planck-Institut für Physik, Föhringer Ring 6, 80805 München (Germany)

Monochromatic photons could be produced in the annihilation or decay of dark matter particles. At high energies, the search for such line features in the cosmic gamma-ray spectrum is essentially background free because plausible astrophysical processes are not expected to produce such a signal. The observation of a gamma-ray line would hence be a 'smoking-gun' signature for dark matter, making the search for such signals particularly attractive. Among the different dark matter models predicting gamma-ray lines, the local supersymmetric extension of the standard model with small R-parity violation and gravitino LSP is of particular interest because it provides a framework where primordial nucleosynthesis, gravitino dark matter and thermal leptogenesis are naturally consistent. Using the two-years Fermi LAT data, we present a dedicated search for gamma-ray lines coming from dark matter annihilation or decay in the Galactic halo. Taking into account the full detector response, and using a binned profile likelihood method, we search for significant line features in the energy spectrum of the diffuse flux observed in different regions of the sky. No evidence for a line signal at the 5σ level is found for photon energies between 1 and 300 GeV, and conservative bounds on dark matter decay rates and annihilation cross sections are presented. Implications for gravitino dark matter in presence of small R-parity violation are discussed, as well as the impact of our results on the prospect for seeing long-lived neutralinos or staus at the LHC.

• OSTI ID: 22277691
• Journal Information: Journal of Cosmology and Astroparticle Physics, Journal Name: Journal of Cosmology and Astroparticle Physics Journal Issue: 05 Vol. 2011; ISSN 1475-7516
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ANNIHILATION
ASTROPHYSICS
COSMIC PHOTONS
COSMOLOGY
CROSS SECTIONS
ENERGY SPECTRA
GAMMA RADIATION
GEV RANGE
GRAVITONS
MONOCHROMATIC RADIATION
NEUTRALINOS
NONLUMINOUS MATTER
NUCLEOSYNTHESIS
PARITY
PARTICLE PRODUCTION
STANDARD MODEL
SUPERSYMMETRY