Abstract
We present new results on the calculation of the dark matter relic abundance within the Higgs induced right-handed neutrino mixing model, solving the associated density matrix equation. For a benchmark value of the dark matter mass MDM = 220 TeV, we show the evolution of the abundance and how this depends on reheat temperature, dark matter lifetime and source right-handed neutrino mass MS, with the assumption MS < MDM. We compare the results with those obtained within the Landau-Zener approximation, showing that the latter largely overestimates the final abundance giving some analytical insight. However, we also notice that since in the density matrix formalism the production is non-resonant, this allows source right-handed neutrino masses below the W boson mass, making dark matter more stable at large mass values. This opens an allowed region for initial vanishing source right-handed neutrino abundance. For example, for MS ≳ 1 GeV, we find MDM≳ 20 PeV. Otherwise, for MS > MW∼ 100 GeV, one has to assume a thermalisation of the source right-handed neutrinos prior to the freeze-in of the dark matter abundance. This results into a large allowed range for MDM, depending on MS. For example, imposing MS ≳ 300 GeV, allowing also successful leptogenesis, we find 00.5 ≲ MDM/TeV ≲ 50. We also discuss in detail leptogenesis with two quasi-degenerate right-handed neutrinos, showing a case when observed dark matter abundance and matter-antimatter asymmetry are simultaneously reproduced. Finally, we comment on how an initial thermal source right-handed neutrino abundance can be justified and on how our results suggest that also the interesting case where MDM < MS, embeddable in usual high scale two right-handed neutrino seesaw models, might be viable.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: 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.