Neutrino mass spectrum from the seesaw extension

TL;DR

This paper investigates how the seesaw mechanism, extended with a second Higgs doublet and right-handed neutrinos, can produce neutrino masses consistent with experimental oscillation data.

Contribution

It provides a detailed analysis of minimal seesaw extensions with one or two right-handed neutrinos and includes one-loop corrections, exploring parameter spaces compatible with observations.

Findings

Neutrino masses can be explained within the model for specific heavy neutrino masses.

Parameter variations can produce neutrino mass differences matching solar and atmospheric data.

The model accommodates both normal and inverted hierarchy scenarios.

Abstract

The smallness of the neutrino masses can be well understood within the seesaw mechanism. We analyse two cases of the minimal extension of the standard model when one or two right-handed fields are added to the three left-handed fields. A second Higgs doublet is included in our model. We calculate the one-loop radiative corrections to the mass parameters which produce mass terms for the neutral leptons. In both cases we numerically analyse light neutrino masses as functions of the heavy neutrinos masses. Parameters of the model are varied to find light neutrino masses that are compatible with experimental data of solar $\Delta m^2_\odot$ and atmospheric $\Delta m^2_\mathrm{atm}$ neutrino oscillations for normal and inverted hierarchy.