Dirac neutrino from the breaking of Peccei-Quinn symmetry

TL;DR

This paper presents a model where Dirac neutrino masses arise from a small Higgs VEV linked to PQ symmetry breaking, connecting neutrino mass, axion dark matter, and the strong CP problem.

Contribution

It introduces a novel mechanism for Dirac neutrino mass generation tied to PQ symmetry breaking without fine-tuning, integrating axion physics.

Findings

Neutrino masses from small Higgs VEVs via a seesaw-like formula.

Connection between neutrino mass, axion dark matter, and strong CP problem.

Compatibility with KSVZ or DFSZ axion models.

Abstract

We propose a model where Dirac neutrino mass is obtained from small vacuum expectation value (VEV) of neutrino-specific Higgs doublet without fine-tuning problem. The small VEV results from a seesaw-like formula with the high energy scale identified as the Peccei-Quinn (PQ) symmetry breaking scale. Axion can be introduced {\it \`a la} KSVZ or DFSZ. The model suggests neutrino mass, solution to the strong CP problem, and dark matter may be mutually interconnected.