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arXiv · 1405.4670

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

Kazunori Nakayama·Fuminobu Takahashi·Tsutomu T. Yanagida
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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.

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Kazunori Nakayama, Fuminobu Takahashi, Tsutomu T. Yanagida. 2014-05-19. Extra light fermions in $E_6$-inspired models and the 3.5 keV X-ray line signal. https://doi.org/10.1016/j.physletb.2014.08.061

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