Neutrino mass in radiatively-broken scale-invariant models

TL;DR

This work analyzes how neutrino masses can emerge in classically scale-invariant models in which the electroweak Higgs is a pseudo-Goldstone boson. It treats both tree-level and radiative mass-generation mechanisms within a minimal extension that includes a real scalar S, showing how singlet-fermion, triplet-Higgs, Zee-type, coloured-scalar, and Babu-type frameworks can be embedded in scale-invariant theories. Radiative neutrino masses are especially appealing, as dimensional transmutation naturally explains the smallness of mν while maintaining a consistent Higgs sector. The study also discusses accidental symmetries, domain-wall issues, and the potential benefits of promoting S to a complex field to realize a Majoron and continuous lepton-number symmetry.

Abstract

Scale invariance may be a classical symmetry which is broken radiatively. This provides a simple way to stabilize the scale of electroweak symmetry breaking against radiative corrections. The simplest phenomenologically successful model of this type involves the addition of one real scalar field to the standard model. In this minimal model the electroweak Higgs can be interpreted as the pseudo-Goldstone boson of broken scale invariance. We study the possible origin of neutrino mass in such models, both at tree-level and radiatively.

Figures (3)

• Figure 1: Neutrino mass in a scale invariant Zee Model
• Figure 2: Neutrino mass in a scale invariant model containing coloured scalar fields $h_{1,2}$.
• Figure 3: Neutrino mass in a scale invariant Babu Model