Neutrino masses beyond the tree level

TL;DR

This paper explores various models for generating Majorana neutrino masses beyond tree level, emphasizing radiative mechanisms that could lead to observable lepton number violation near the electroweak scale.

Contribution

It provides a general classification framework for neutrino mass models based on the loop level of the effective operator and discusses phenomenological implications of radiative models.

Findings

Radiative models can induce lepton number violation at electroweak scale.

Analysis of Babu-Zee and supersymmetric R-parity violating models.

Potential experimental signatures of radiative neutrino mass mechanisms.

Abstract

Models for Majorana neutrino masses can be classified according to the level in perturbation theory at which the effective dimension five operator $LLHH$ is realized. The possibilities range from the tree-level up to the three-loop level realizations. We discuss some general aspects of this approach and speculate about a model independent classification of the possible cases. Among all the realizations, those in which the effective operator is induced by radiative corrections open the possibility for lepton number violation near -or at- the electroweak scale. We discuss some phenomenological aspects of two generic radiative realizations: the Babu-Zee model and supersymmetric models with bilinear R-parity violation.