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Abstract

We propose a unified model of scalar particles that addresses the flavour
hierarchies, solves the strong CP problem, delivers a dark matter candidate,
and provides the trigger for electroweak symmetry breaking. Besides furnishing
a unification of the recently proposed axiflavon with a Goldstone-Higgs sector,
the scenario can also be seen as adding a model of flavour (and strong CP
conservation along with axion dark matter) to elementary Goldstone-Higgs
setups. In particular, we derive bounds on the axion decay constant from the
need to generate a SM-like Higgs potential at low energies, which we confront
with constraints from flavour physics and cosmology. In the minimal
implementation, we find that the axion decay constant is restricted to a thin
stripe of $f_a \approx (10^{11}-10^{12})$ GeV, while adding right-handed
neutrinos allows to realize a heavy-axion model at lower energies, down to $f_a
\sim 10$ TeV.