The Axiflavon

TL;DR

This paper proposes a simple $U(1)_H$ flavor symmetry model that naturally links the flavor hierarchy to axion properties, providing a unified solution to the strong CP problem and dark matter, with testable predictions.

Contribution

It introduces a novel $U(1)_H$ flavor symmetry framework that connects fermion mass hierarchies to axion characteristics, making the model highly predictive and experimentally accessible.

Findings

Axion mass and photon coupling ratio are predicted within a small range.

Fermion couplings to axions are determined by flavor hierarchies.

Model offers testable predictions for future axion and flavor experiments.

Abstract

We show that solving the flavor problem of the Standard Model with a simple $U(1)_H$ flavor symmetry naturally leads to an axion that solves the strong CP problem and constitutes a viable Dark Matter candidate. In this framework, the ratio of the axion mass and its coupling to photons is related to the SM fermion masses and predicted within a small range, as a direct result of the observed hierarchies in quark and charged lepton masses. The same hierarchies determine the axion couplings to fermions, making the framework very predictive and experimentally testable by future axion and precision flavor experiments.