Chiral Froggatt-Nielsen models, gauge anomalies and flavourful axions

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. * quentin.bonnefoy@desy.de †

Flavoured warped axion

“…In 4D flavour models of the Froggatt-Nielsen type [27] where the axion is the phase of the flavon field responsible for generating fermion mass hierarchies, there are also flavour off-diagonal axion-fermion couplings [28][29][30][31][32][33]. Indeed, in such models the Yukawa couplings JHEP04(2021)084 GeV.…”

Quark flavor phenomenology of the QCD axion

“…[56][57][58][59][60][61][62][63][64][65]. Finally, flavored PQ symmetries can arise also in the context of minimal-flavor violation (MFV) [66,67] or as accidental symmetries in models with gauged flavor symmetries [68][69][70][71].…”

Ultralight scalars in leptonic observables

“…Therefore, restricting the phenomenological exploration to just pseudoscalars would miss a relatively large number of well-motivated scenarios. This has actually been the case in many recent works [29][30][31][32][33][34][35][36][37][38][39], which were mainly interested in the phenomenology of flavored axions (or ALPs) and majorons [40].…”