Neutrinoless Double Beta Decay in Type I+II Seesaw Models

TL;DR

This paper analyzes neutrinoless double beta decay within a left-right symmetric model incorporating both type I and type II seesaw mechanisms, exploring new physics contributions and constraining model parameters based on experimental limits.

Contribution

It provides a comparative analysis of neutrinoless double beta decay contributions from type I and type II seesaw dominance in a left-right symmetric framework, including combined effects.

Findings

New physics sources significantly affect decay rates.

Constraints on neutrino masses and model parameters are derived.

Predictions are consistent with current experimental bounds.

Abstract

We study neutrinoless double beta decay in left-right symmetric extension of the standard model with type I and type II seesaw origin of neutrino masses. Due to the enhanced gauge symmetry as well as extended scalar sector, there are several new physics sources of neutrinoless double beta decay in this model. Ignoring the left-right gauge boson mixing and heavy-light neutrino mixing, we first compute the contributions to neutrinoless double beta decay for type I and type II dominant seesaw separately and compare with the standard light neutrino contributions. We then repeat the exercise by considering the presence of both type I and type II seesaw, having non-negligible contributions to light neutrino masses and show the difference in results from individual seesaw cases. Assuming the new gauge bosons and scalars to be around a TeV, we constrain different parameters of the model including both heavy and light neutrino masses from the requirement of keeping the new physics contribution to neutrinoless double beta decay amplitude below the upper limit set by the GERDA experiment and also satisfying bounds from lepton flavor violation, cosmology and colliders.