Fermion mixings in SU(9) family unification

In an SU(9) model of gauged family unification, we propose an explanation for why angles observed in the lepton flavor (PMNS) mixing matrix are significantly larger than those measured for any analogous quark flavor (KM) mixing angle. It is directly related to a see-saw mechanism that we assume to be responsible for the generation of neutrino masses. Our model is more constrained and therefore even more predictive than a model previously proposed by Barr.