Exploring $0\nu \beta \beta$ and Leptogenesis in the Alternative Left-Right Model

Abstract

We investigate the possibility of neutrinoless double beta decay ($0\nu \beta \beta$) 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 $0\nu \beta \beta$ through vector-scalar ($WH$) mediation. For moderate masses of the relevant charged Higgs boson ($M_{H_1^{\pm }}\sim 200$ GeV), the half-life of $T_{\frac{1}{2}}^{WH}$ is $\sim 3\times 10^{26}\mathrm{yrs}$ for both the case of ${}^{76}$Ge and ${}^{136}$Xe, 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, $\epsilon \sim 10^{-6}$, for small Dirac phases and without any fine tuning.

22 pages, 3 figures, Matches the published version