Origin of Yukawa couplings for Higgs bosons and leptoquarks

We propose a model in which the Yukawa couplings of Higgs doublets are related to the couplings of the chiral fermions to a scalar leptoquark triplet. This is due to their common origin via mixing with a vectorlike family distinguished by a discrete Z5 symmetry, under which only the three chiral families are neutral. The model predicts lepton nonuniversality in B to K decays, depending on the leptoquark mass, Vts and mμ/mτ. The model can only consistently explain the anomalies in RK(∗) for a leptoquark mass close to the collider lower bound of about 1 TeV. Constraints from Bs-Bs mixing and eventually τ→μγ become relevant for low leptoquark masses and large couplings, while μ→eγ remains automatically under control due to the absence of leptoquark couplings to the electron in this model.