Intimate relationship between sterile neutrino Dark Matter and extra radiation in the early Universe

31 Aug 2021, 17:10
Talk in parallel session Cosmology and particle physics Discussion Panel Cosmology 2


Manibrata Sen (UC, Berkeley)


keV-scale gauge-singlet fermions, allowed to mix with the active neutrinos, are elegant dark matter (DM) candidates. They are produced in the early universe via the Dodelson-Widrow mechanism and can be detected as they decay very slowly, emitting X-rays. In the absence of new physics, this hypothesis is virtually ruled out by astrophysical observations. In this talk, I will demonstrate that new interactions among the active neutrinos allow these sterile neutrinos to make up all the DM while safely evading all current experimental bounds. Neutrino interactions mediated by a sub-MeV scalar can also lead a lower bound on the amount of extra radiation in the early Universe. Such models can, therefore, receive strong constraints from next generation cosmology experiments, like CMB-S4

Reference to paper (DOI or arXiv) (accepted in PRL)

Primary authors

Manibrata Sen (UC, Berkeley) Kevin Kelly (Fermilab) Yue Zhang (Carleton University)

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