Left-Right Symmetric Neutrino Mass Model without Scalar Bi-doublet

Abstract

We consider a left-right symmetric model with an $SU(2)_L$ and an $SU(2)_R$ scalar doublet but without the scalar bidoublet. The charged fermion masses in this model are generated via a universal seesaw mechanism. We add a set of three gauge singlet neutral fermions with Majorana masses of the order of a TeV. The masses for the left-handed neutrinos are naturally small in this model because they occur only at one-loop and are generated through a see-saw mechanism. By an appropriate choice of the Yukawa couplings of the $SU(2)_L$ doublet and the masses of the gauge singlet fermions, it is possible to implement resonant leptogenesis at TeV scale. The right-handed sector of the model, through appropriate values of the Yukawa couplings of the $SU(2)_R$ doublet, leads to a warm dark matter candidate in the lightest right-handed neutrino with a mass of a few keV and an observable effective electron mass for neutrinoless double beta decay $m_{ββ}$.