Galactic 511 keV line from MeV millicharged dark matter

Abstract

We present a possible explanation of the recently observed 511 keV $\gamma$-ray anomaly with a new ``millicharged'' fermion. The new fermion is light ($\mathcal{O}(\mathrm{MeV})$) but has never been observed by any collider experiments mainly because of its tiny electromagnetic charge $\epsilon e$. We show that constraints from its relic density in the Universe and collider experiments allow a parameter range such that the 511 keV cosmic $\gamma$-ray emission from the galactic bulge may be due to positron production from this millicharged fermion.

14 pages, 3 figures; To appear in Phys. Rev. D

References in corpus (5)

• Exciting Dark Matter and the INTEGRAL/SPI 511 keV signal
• Gamma-ray continuum emission from the inner Galactic region as observed with INTEGRAL/SPI
• Light from the Hidden Sector
• PVLAS experiment, star cooling and BBN constraints: Possible interpretation with temperature dependent gauge symmetry breaking
• Gauge mediated supersymmetry breaking without exotics in orbifold compactification

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