Massive neutrinos and invisible axion minimally connected

TL;DR

This paper explores minimal scalar extensions of the Standard Model that connect massive neutrinos with an invisible axion, addressing the strong CP problem and dark matter within a unified framework.

Contribution

It introduces a minimal, renormalizable model linking neutrino masses and axion physics, applying it to type-II seesaw and loop-induced neutrino mass models.

Findings

Provides a unified framework for neutrino masses and axion dark matter.

Analyzes naturalness, vacuum stability, and baryogenesis implications.

Demonstrates models compatible with neutrino oscillation data.

Abstract

We survey a few minimal scalar extensions of the standard electroweak model that provide a simple setup for massive neutrinos in connection with an invisible axion. The presence of a chiral $U(1)$ \`a la Peccei-Quinn drives the pattern of Majorana neutrino masses while providing a dynamical solution to the strong CP problem and an axion as a dark matter candidate. We paradigmatically apply such a renormalizable framework to type-II seesaw and to two viable models for neutrino oscillations where the neutrino masses arise at one and two loops, respectively. We comment on the naturalness of the effective setups as well as on their implications for vacuum stability and electroweak baryogenesis.