Testing neutrino mass generation mechanisms from the lepton flavor violating decay of the Higgs boson

TL;DR

This paper explores how detecting lepton flavor violating Higgs decays can constrain or exclude various neutrino mass generation models, highlighting that many Majorana models are incompatible with such observations.

Contribution

It systematically analyzes the compatibility of different neutrino mass models with potential signals of lepton flavor violation in Higgs decays.

Findings

Many Majorana neutrino mass models are incompatible with observed lepton flavor violating Higgs decays.

Some radiative Dirac neutrino mass models can produce observable lepton flavor violation.

Detection of $h o au au^ ext{'}$ could exclude several neutrino mass generation mechanisms.

Abstract

We investigate how observations of the lepton flavor violating decay of the Higgs boson ($h \to \ell\ell^\prime$) can narrow down models of neutrino mass generation mechanisms, which were systematically studied in Refs. [1,2] by focusing on the combination of new Yukawa coupling matrices with leptons. We find that a wide class of models for neutrino masses can be excluded if evidence for $h \to \ell\ell^\prime$ is really obtained in the current or future collider experiments. In particular, simple models of Majorana neutrino masses cannot be compatible with the observation of $h \to \ell\ell^\prime$. It is also found that some of the simple models to generate masses of Dirac neutrinos radiatively can be compatible with a significant rate of the $h \to \ell\ell^\prime$ process.