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arXiv · 1406.6481

X-ray Line from the Dark Transition Electric Dipole

Chao-Qiang Geng·Da Huang·Lu-Hsing Tsai
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Abstract

We study a two-component dark matter (DM) model in which the two Majorana fermionic DM components with nearly degenerate masses are stabilized by an $Z_2$ symmetry and interact with the right-handed muon and tau only via real Yukawa couplings, together with an additional $Z_2$-odd singly-charged scalar. In this setup, the decay from the heavy DM to the lighter one via the transition electric dipole yields the 3.55 keV X-ray signal observed recently. The Yukawa couplings in the dark sector are assumed to be hierarchical, so that the observed DM relic abundance can be achieved with the leading s-wave amplitudes without a fine-tuning. We also consider the constraints from flavor physics, DM direct detections and collider searches, respectively.

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Chao-Qiang Geng, Da Huang, Lu-Hsing Tsai. 2014-07-27. X-ray Line from the Dark Transition Electric Dipole. https://doi.org/10.1007/jhep08(2014)086

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