Chiral Froggatt-Nielsen models, gauge anomalies and flavourful axions

TL;DR

This paper explores UV-complete Froggatt-Nielsen models with chiral heavy fields, enabling gauged flavour symmetries without extra fermions, and examines the resulting flavourful axions with enhanced matter couplings.

Contribution

It introduces models where chiral heavy fields modify anomalies, allowing gauged flavour symmetries without spectator fermions, and analyzes the properties of associated flavourful axions.

Findings

Gauged Froggatt-Nielsen models without spectator fermions are feasible.

Flavourful axions in these models have stronger couplings to matter.

Specific examples demonstrate anomaly cancellation and axion phenomenology.

Abstract

We study UV-complete Froggatt-Nielsen-like models for the generation of mass and mixing hierarchies, assuming that the integrated heavy fields are chiral with respect to an abelian Froggatt-Nielsen symmetry. It modifies the mixed anomalies with respect to the Standard Model gauge group, which opens up the possibility to gauge the Froggatt-Nielsen symmetry without the need to introduce additional spectator fermions, while keeping mass matrices usually associated to anomalous flavour symmetries. We give specific examples where this happens, and we study the flavourful axion which arises from an accidental Peccei-Quinn symmetry in some of those models. Such an axion is typically more coupled to matter than in models with spectator fermions.