Classification of three-family flavoured DFSZ axion models that have no domain wall problem

Abstract

We provide an exhaustive classification of three-family DFSZ axion models that have no cosmological domain wall problem. This result is obtained by making the Peccei-Quinn symmetry flavour dependent in certain specific ways, thus reinforcing a possible connection between the strong CP problem and the flavour puzzle. Known DFSZ flavour variants such as the top-specific model emerge as special cases. Key features of the phenomenology of these models are briefly discussed.

Cosmology of axion dark matter

“…For the DFSZ case, this requires the PQ symmetry to be made flavour-dependent, see the recent Ref. [150] for a list of DFSZ models with no domain-wall number problem.…”