Neutrino parameters in the Planck-scale lepton number breaking scenario with extended scalar sectors

TL;DR

This paper explores how two-loop quantum effects and extended scalar sectors at the Planck scale influence right-handed neutrino masses and active neutrino phenomenology, aligning theoretical models with experimental data.

Contribution

It introduces extended scalar sector models at the Planck scale that naturally produce realistic neutrino masses and hierarchies through quantum effects.

Findings

Two-loop effects can dominate light right-handed neutrino masses.

Extended scalar sectors can generate realistic active neutrino masses.

Models achieve neutrino mass scales and hierarchies consistent with observations.

Abstract

Two-loop effects on the right-handed neutrino masses can have an impact on the low-energy phenomenology, especially when the right-handed neutrino mass spectrum is very hierarchical at the cut-off scale. In this case, the physical masses of the lighter right-handed neutrinos can be dominated by quantum effects induced by the heavier ones. Further, if the heaviest right-handed neutrino mass is at around the Planck scale, two-loop effects on the right-handed neutrino masses generate, through the seesaw mechanism, an active neutrino mass which is in the ballpark of the experimental values. In this paper we investigate extensions of the Planck-scale lepton number breaking scenario by additional Higgs doublets (inert or not). We find that under reasonable assumptions these models lead simultaneously to an overall neutrino mass scale and to a neutrino mass hierarchy in qualitative agreement with observations.