Natural TeV-Scale Left-Right Seesaw for Neutrinos and Experimental Tests

TL;DR

This paper proposes a TeV-scale left-right symmetric model for neutrino masses that predicts observable lepton flavor violation and neutrinoless double beta decay signals, testable at current and future experiments.

Contribution

It introduces a natural, ultraviolet-complete left-right seesaw model with large light-heavy neutrino mixing and specific experimental signatures at TeV energies.

Findings

Potential to observe lepton flavor violation in upcoming experiments

Predictions for neutrinoless double beta decay signals

Constraints on model parameters from experimental limits

Abstract

We present a TeV-scale left-right ultraviolet completion of type-I seesaw for neutrino masses based on the $SU(2)_L\times SU(2)_R\times U(1)_{B-L}$ gauge group without parity, which leads to "large" light-heavy neutrino mixing while keeping the neutrino masses small in a natural manner guaranteed by discrete symmetries. We point out specific observable implications of this class of models if the $SU(2)_R$-breaking scale is of order 5 TeV, in searches for lepton flavor violating processes such as $\mu\to e\gamma$, $\mu\to 3 e$ and $\mu-e$ conversion in nuclei, and lepton number violating processes such as neutrinoless double beta decay as well as at the LHC. In particular, if the upper limit on BR$(\mu\to e\gamma)$ improves by one order of magnitude, a large range of the parameters of the model would be ruled out.