$0 \nu\, \beta \beta$ decay process in left-right symmetric models without scalar Bidoublet

TL;DR

This paper proposes a modified left-right symmetric model with two Higgs doublets and extra charged iso-singlet fields, analyzing neutrinoless double beta decay contributions with MeV-scale right-handed neutrinos and potential collider implications.

Contribution

It introduces a novel left-right symmetric model without scalar bidoublets, featuring a different Higgs sector and fermion mass generation via heavy isosinglet fields, and explores neutrinoless double beta decay in this context.

Findings

Right-handed Majorana neutrino can be in MeV range.

Right-handed current contribution to neutrinoless double beta decay can be significant.

Potential to probe new physics at LHC with TeV-scale $W_R$ bosons.

Abstract

We present an alternative formulation of the left-right symmetric theory where the scalar sector consists of two Higgs doublets which differs from the standard version of the left-right model that makes use of $L-$ and $R-$ Higgs triplets and a Higgs bi-doublet. The basic idea is to consider few extra charged iso-singlet fields and the fermion masses can be realized by integrating out these heavy isosinglet fields. We also give a detailed discussion on neutrinoless double beta decay in this particular left-right symmetric theory where the right-handed Majorana neutrino can be of MeV range. With this right-handed Majorana mass around MeV scale, the contribution to neutrinoless double beta decay coming from the right-handed current can be comparable with the contributions coming from the standard left-handed sector only if the right-handed gauge boson mass is around 5 TeV, and with this operative scale of $W_R$ around few TeV, it is possible to probe at LHC. We have briefly commented on cosmological constraints coming from the big-bang nucleosynthesis and Universe cosmology to the right-handed neutrinos involved in this discussion.