Naturalness and lepton number/flavor violation in inverse seesaw models

TL;DR

This paper explores an inverse seesaw model with additional neutrinos, highlighting how naturalness constraints lead to enhanced neutrinoless double beta decay rates and significant Higgs mass corrections, with implications for future experiments.

Contribution

It introduces a specific inverse seesaw model with three right-handed and three sterile neutrinos, analyzing naturalness, decay rates, and Higgs corrections, providing new analytic and numerical insights.

Findings

Neutrinoless double beta decay rate can be over ten times the standard prediction.

Heavy neutrino contributions significantly impact Higgs mass corrections.

Most of the parameter space can be tested by future neutrinoless double beta decay and $0$ conversion experiments.

Abstract

We introduce three right-handed neutrinos and three sterile neutrinos, and consider an inverse seesaw mechanism for neutrino mass generation. From naturalness point of view, their Majorana masses should be small, while it induces a large neutrino Yukawa coupling. Then, a neutrinoless double beta decay rate can be enhanced, and a sizable Higgs mass correction is inevitable. We find that the enhancement rate can be more than ten times compared with a standard prediction from light neutrino contribution alone, and an analytic form of heavy neutrino contributions to the Higgs mass correction. In addition, we numerically analyze the model, and find almost all parameter space of the model can be complementarily searched by future experiments of neutrinoless double beta decay and $\mu \to e$ conversion.