Exploring 0νββ and leptogenesis in the alternative left-right model

Abstract

We investigate the possibility of neutrinoless double beta decay (0νββ) and leptogenesis within the alternative left-right model (ALRM). Unlike the usual left-right symmetric model, ALRM features a Majorana right-handed neutrino which does not carry any charge. Further, in this picture the down-type quark and the charged leptons receive mass through the additional left-handed scalar field, rather than the usual doublet. Together, these features conspire to generate significant contributions to the 0νββ through vector-scalar (WH) mediation. For moderate masses of the relevant charged Higgs boson (MH1±∼200 GeV), the half-life of T12WH is ∼3×1026 yrs for both the case of Ge76 and Xe136, well within the sensitivity expected by future experiments. Invoking the resonant leptogenesis, CP violation arising from the right-handed neutrino decay could be the required order to generate the correct baryogenesis, ϵ∼10-6, for small Dirac phases and without any fine tuning.