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Probing neutrino decays with the cosmic microwave background

Steen Hannestad
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Abstract

We investigate in detail the possibility of constraining neutrino decays with data from the cosmic microwave background radiation (CMBR). Two generic decays are considered ν_H -> ν_L ϕand ν_H -> ν_L ν_L_bar ν_L. We have solved the momentum dependent Boltzmann equation in order to account for possible relativistic decays. Doing this we estimate that any neutrino with mass m > 1 eV decaying before the present should be detectable with future CMBR data. Combining this result with other results on stable neutrinos, any neutrino mass of the order 1 eV should be detectable.

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Steen Hannestad. 1999-03-31. Probing neutrino decays with the cosmic microwave background. https://doi.org/10.1103/physrevd.59.125020

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