RK(*) and the origin of Yukawa couplings

We explore the possibility that the semi-leptonic B decay ratios R-K(*) which violate mu - e universality are related to the origin of the fermion Yukawa couplings in the Standard Model. Some time ago, a vector-like fourth family (without a Z') was used to generate fermion mass hierarchies and mixing patterns without introducing any family symmetry. Recently the idea of inducing flavourful Z' couplings via mixing with a vector-like fourth family which carries gauged U(1)' charges has been proposed as a simple way of producing controlled flavour universality violation while elegantly cancelling anomalies. We show that the fusion of these two ideas provides a nice connection between R-K(*) and the origin of Yukawa couplings in the quark sector. However the lepton sector requires some tuning of Yukawa couplings to obtain the desired coupling of Z' to muons.