Is There a Dark Matter Signal in the Galactic Positron Annihilation Radiation?

Abstract

Assuming Galactic positrons do not go far before annhilating, a difference between the observed 511 keV annihilation flux distribution and that of positron production, expected from beta-plus decay in Galactic iron nucleosynthesis, was evoked as evidence of a new source and a signal of dark matter. We show, however, that the dark mater sources can not account for the observed positronium fraction without extensive propagation. Yet with such propagation, standard nucleosynthetic sources can fully account for the spatial differences and the positronium fraction, leaving no signal for dark mater to explain.

4 pages, no figures, 85 references, revised version accepted for publication in Physical Review Letters

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• Exciting Dark Matter and the INTEGRAL/SPI 511 keV signal
• Spatial distribution of interstellar gas in the innermost 3 kpc of our Galaxy
• Investigating electron interacting dark matter
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Cited by in corpus (5)

• Nonabelian dark matter: models and constraints
• Updated cosmic-ray and radio constraints on light dark matter: Implications for the GeV gamma-ray excess at the Galactic center
• Scalar Dark Matter Candidates -- Revisited
• Two-photon Annihilation of Positrons with K-shell Electrons of H-like ions
• Updated Constraints on the Injection Energy of Positrons Generating the Galactic 511 keV $\gamma$-ray line