Extra light fermions in $E_6$-inspired models and the 3.5 keV X-ray line signal

Abstract

We propose a scenario in which extra light fermions in an $E_6$-inspired U(1) extension of the standard model constitute the dark matter, as a simple variation of our model for dark radiation presented in 2010. Interestingly, for the light fermions of mass about 7 keV, they radiatively decay into active neutrinos and photons with a lifetime in the range of $10^{27}-10^{28}$ seconds, which naturally explains the recently discovered 3.5 keV X-ray line signal.

7 pages

References in corpus (4)

• Light Sterile Neutrinos: A White Paper
• Sterile neutrino dark matter in $B-L$ extension of the standard model and galactic 511 keV line
• A theory of extra radiation in the Universe
• Number-Theory Dark Matter

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• A Fresh Look at keV Sterile Neutrino Dark Matter from Frozen-In Scalars
• 3.5-keV X-ray line from nearly-degenerate WIMP dark matter decays
• X-ray Line from the Dark Transition Electric Dipole
• Exploring X-Ray Lines as Scotogenic Signals
• Non-abelian Dark Matter Solutions for Galactic Gamma-ray Excess and Perseus 3.5 keV X-ray Line
• 3.5 keV X-ray line and R-Parity Conserving Supersymmetry
• 3.5 keV Galactic Emission Line as a Signal from the Hidden Sector
• Neutrinos from the Early Universe and Physics Beyond Standard Models