Axion framework with color-mediated Dirac neutrino masses

TL;DR

This paper introduces a KSVZ-type axion model where vector-like quarks and colored scalars generate Dirac neutrino masses radiatively, linking the solution to the strong CP problem with dark matter and testable axion signatures.

Contribution

It presents a novel axion framework incorporating vector-like quarks and colored scalars to produce Dirac neutrino masses radiatively, with detailed exploration of viable representations and experimental predictions.

Findings

Distinct axion-to-photon couplings predicted

Potential for flavor-violating quark-axion interactions

Framework compatible with dark matter observations

Abstract

We propose a KSVZ-type axion framework in which vector-like quarks (VLQ) and colored scalars generate Dirac neutrino masses radiatively. The global Peccei-Quinn symmetry (under which the exotic fermions are charged) addresses the strong CP problem and ensures the Dirac nature of neutrinos. The axion also accounts for the observed cosmological dark matter. We systematically explore all viable VLQ representations. Depending on the specific scenario, the framework predicts distinct axion-to-photon couplings, testable through haloscope and helioscope experiments, as well as potentially significant flavor-violating quark-axion interactions.