Wess-Zumino-Witten Interactions of Axions: Three-Flavor

TL;DR

This paper develops a comprehensive Lagrangian for axion interactions with mesons in the three-flavor quark model, incorporating chiral and WZW terms, instanton effects, and providing decay width calculations.

Contribution

It introduces a complete, invariant Lagrangian for axion-meson interactions that includes instanton effects and applies it to compute axion decay widths.

Findings

The Lagrangian remains invariant under chiral phase rotations.

Explicit decay widths for GeV-scale axions into mesons are calculated.

The framework unifies axion interactions with mesons and gauge bosons.

Abstract

We present a complete Lagrangian describing axion interactions with pseudoscalar and (axial-)vector mesons within the three light-flavor quark framework. This formulation incorporates both the standard chiral Lagrangian and the full Wess-Zumino-Witten (WZW) term. By including instanton effects associated with the anomalous $U(1)_A$ symmetry, we demonstrate that physical observables remain invariant under arbitrary chiral phase rotations of the quark fields. This comprehensive Lagrangian provides a robust and consistent framework for exploring axion phenomenology through its interactions with mesons and gauge bosons. As a demonstration, we compute the decay widths of GeV-scale axions into various mesonic final states for several benchmark axion models.