Left-Right Symmetric Model without Higgs Triplets

TL;DR

This paper introduces a minimal left-right symmetric model replacing Higgs triplets with doublets, generating neutrino masses via two-loop diagrams, and explores its phenomenological implications across collider, cosmological, and astrophysical contexts.

Contribution

It presents a novel minimal model with Higgs doublets instead of triplets, providing a consistent framework for neutrino masses and collider phenomenology.

Findings

The model fits neutrino oscillation data across a wide $W_R$ mass range.

Right-handed neutrino masses can be in the MeV range at TeV-scale $W_R$.

A lower limit of 390 GeV on the charged scalar $ exteta^+$ mass from LHC data.

Abstract

We develop a minimal left-right symmetric model based on the gauge group $SU(3)_C \otimes SU(2)_L \otimes SU(2)_R \otimes U(1)_{B-L}$ wherein the Higgs triplets conventionally employed for symmetry breaking are replaced by Higgs doublets. Majorana masses for the right-handed neutrinos $(\nu_R$) are induced via two-loop diagrams involving a charged scalar field $\eta^+$. This setup is shown to provide excellent fits to neutrino oscillation data via the seesaw mechanism for the entire range of the $W_R^\pm$ mass, from TeV to the GUT scale. When the $W_R^\pm$ mass is at the TeV scale, the $\nu_R$ masses turn out to be in the MeV range. We analyze constraints from low energy experiments, early universe cosmology and from supernova 1987a on such a scenario and show its consistency. We also study collider implications of a relatively light $\eta^+$ scalar through its decay into multi-lepton final states and derive a lower limit of 390 GeV on its mass from the LHC, which can be improved to 555 GeV in its high luminosity run.