Probing Models of Neutrino Masses via the Flavor Structure of the Mass Matrix

TL;DR

This paper classifies models generating Majorana neutrino masses based on their Yukawa interaction structures, providing a framework to distinguish models experimentally without detailed scalar potential analysis.

Contribution

It introduces a classification scheme for neutrino mass models based solely on Yukawa interaction combinations, simplifying model discrimination.

Findings

Yukawa interactions with leptons alone form three distinct groups.

Yukawa interactions involving leptons and gauge singlet fermions also fall into three groups.

The classification aids experimental differentiation of neutrino mass models.

Abstract

We discuss what kinds of combinations of Yukawa interactions can generate the Majorana neutrino mass matrix. We concentrate on the flavor structure of the neutrino mass matrix because it does not depend on details of the models except for Yukawa interactions while determination of the overall scale of the mass matrix requires to specify also the scalar potential and masses of new particles. Thus, models to generate Majorana neutrino mass matrix can be efficiently classified according to the combination of Yukawa interactions. We first investigate the case where Yukawa interactions with only leptons are utilized. Next, we consider the case with Yukawa interactions between leptons and gauge singlet fermions, which have the odd parity under the unbroken Z_2 symmetry. We show that combinations of Yukawa interactions for these cases can be classified into only three groups. Our classification would be useful for the efficient discrimination of models via experimental tests for not each model but just three groups of models.