Effective Interactions for the SM Fermion Mass Hierarchy and their Possible UV Realization

Abstract We build an extended two Higgs doublet model theory with spontaneously broken $U(1) _{X}$ global symmetry, where the tree-level universal seesaw mechanism generates the mass hierarchy of the Standard Model charged fermions and the Zee–Babu mechanism produces tiny active neutrino masses. The third family of SM charged fermions gets tree-level masses from Yukawa interactions involving the Higgs doublets $H_1$ (for the top quark) and $H_2$ (for the bottom quark and tau lepton). The model under consideration is consistent with SM fermion masses and mixings, with the muon and electron $g-2$ anomalies, and successfully accommodates the constraints arising from charged-lepton-flavor violation and meson oscillations. The proposed model predicts rates for charged-lepton-flavor-violating decays within the reach of forthcoming experiments.