Neutrino masses, intermediate mass scales, and cosmology

We analyze the neutrino mass spectrum in the context of the $\mathrm{SU}{\mathrm{}\left(2\right)\mathrm{}}_L\times \mathrm{SU}{\mathrm{}\left(2\right)\mathrm{}}_R\times \mathrm{U}{\mathrm{}\left(1\right)\mathrm{}}_{B-L}$ gauge theory, with left-right—symmetry breaking at an intermediate scale ∼${10}^6$ GeV. We show that this model allows for a rather sharp neutrino mass spectrum consistent with the cosmological constraints. The novel element in our analysis is the connection between cosmological baryon production and neutrino masses. As a consequence, it turns out that the widespread feeling of a possible conflict with cosmological constraints on neutrino masses is unjustified.