Can new generations explain neutrino masses?

TL;DR

This paper investigates whether adding extra generations of fermions and right-handed neutrinos to the standard model can naturally explain the small neutrino masses, focusing on a two-loop mass generation mechanism.

Contribution

It introduces a model with two extra fermion generations and right-handed neutrinos, demonstrating its ability to fit observed neutrino masses and mixings.

Findings

N=1 extra generation is insufficient to fit data

N=2 extra generations can successfully explain neutrino masses

The model predicts potential signals for future experiments

Abstract

In this talk we explore the possibility that the smallness of the observed neutrino masses is naturally understood in a modified version of the standard model with N extra generations of fermions and N right-handed neutrinos, in which light neutrino masses are generated at two loops. We find that with N = 1 it is not possible to fit the observed spectrum of masses and mixings while with N = 2 it is. Within this extension, we analyse the parameters which are allowed and the possible phenomenological signals of the model in future experiments. Contribution to the proceedings of Les Rencontres de Moriond EW 2011, Young Scientist Forum.