Abstract
We revisit a model in which neutrino masses and mixing are described by a two right-handed (RH) neutrino seesaw scenario, implying a strictly hierarchical light neutrino spectrum. A third decoupled RH neutrino, NDM with mass MDM, plays the role of cold dark matter (DM) and is produced by the mixing with a source RH neutrino, NS with mass MS, induced by Higgs portal interactions. The same interactions are also responsible for NDM decays. We discuss in detail the constraints coming from DM abundance and stability conditions showing that in the hierarchical case, for MDM ≫ MS, there is an allowed window on MDM values necessarily implying a contribution, from DM decays, to the high-energy neutrino flux recently detected by IceCube. We also show how the model can explain the matter-antimatter asymmetry of the Universe via leptogenesis in the quasi-degenerate limit. In this case, the DM mass should be within the range 300 GeV ≲ MS < MDM ≲ 10 PeV. We discuss the specific properties of this high-energy neutrino flux and show the predicted event spectrum for two exemplary cases. Although DM decays, with a relatively hard spectrum, cannot account for all the IceCube high-energy data, we illustrate how this extra source of high-energy neutrinos could reasonably explain some potential features in the observed spectrum. In this way, this represents a unified scenario for leptogenesis and DM that could be tested during the next years with more high-energy neutrino events.
Highlights
The possibility of explaining the dark matter (DM) and baryon asymmetry of the Universe within a unified picture is an attractive idea, intensively explored during recent years [1]
In particular we show that relaxing the assumption of ultra-relativistic thermal NS abundance at the resonance, the hierarchical case (MDM MS) becomes viable extending the range of allowed values for MDM
As we discussed in detail, in the scenario of cold DM from RH neutrino mixing, the same new interactions are responsible both for NDM production and DM decays, with much stronger predictive power compared to models one can imagine where there is one kind of interaction responsible for production and another responsible for decays where one has in any case freedom to reproduce both DM abundance and a contribution to IceCube neutrinos
Summary
The possibility of explaining the dark matter (DM) and baryon asymmetry of the Universe within a unified picture is an attractive idea, intensively explored during recent years [1]. Very heavy DM decays have been proposed to account for part or all of these events [16, 17] and different constraints, within different models, have been presented [18,19,20,21,22,23,24,25,26,27,28,29], showing that this could be a potential explanation of the observed events (or part of them) Encouraged by this phenomenological picture, in this paper we revisit the cold DM RH neutrino mixing scenario discussing a few important aspects and showing how to test it with high-energy neutrino detectors such as IceCube and showing explicitly how the same set up can accommodate the matter-antimatter asymmetry of the Universe via leptogenesis, as first pointed out in Refs.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
