keV scale νᵣ dark matter and its detection in β decay experiment

الأصل · EN

We study dark matter(DM) in the model with one keV scale right-handed neutrino νᵣ₁ and two GeV scale right-handed neutrinos νᵣ₂,₃, the νSM. We find that one of the GeV scale right-handed neutrinos can have much longer lifetime than the other when two GeV scale right-handed neutrinos are degenerate. We show that mass and mixing of light neutrinos can be explained in this case. Significant entropy release can be generated in a reheating produced by the decay of one of the GeV scale νᵣ. The density of νᵣ₁ DM can be diluted by two orders of magnitude and the mixing of νᵣ₁ with active neutrinos is allowed to be much larger, reaching the bound from X-ray observation. This mixing can lead to sizeable rate of νᵣ₁ capture by radioactive nuclei. The νᵣ₁ capture events are mono-energetic electrons with keV scale energy away from the beta decay spectrum. This is a new way to detect DM in the universe.