Freeze-in and freeze-out generation of lepton asymmetries after baryogenesis in the $\nu$MSM

Shintaro Eijima, Mikhail Shaposhnikov, Inar Timiryasov

The $\nu$MSM -- an extension of the Standard Model by three relatively light singlet Majorana fermions $N_{1,2,3}$ -- allows for the generation of lepton asymmetry which is several o…