We formulate a viable low-scale seesaw model, where the masses for the standard model (SM) charged fermions lighter than the top quark emerge from a universal seesaw mechanism mediated by charged vectorlike fermions. The small light active neutrino masses are produced from an inverse seesaw mechanism mediated by right-handed Majorana neutrinos. Our model is based on the A4 family symmetry, supplemented by cyclic symmetries, whose spontaneous breaking produces the observed pattern of SM fermion masses and mixings. The model can accommodate the muon and electron anomalous magnetic dipole moments and predicts strongly suppressed µ → eγ and τ → µγ decay rates, but allows a τ → eγ decay within the reach of the forthcoming experiments.
We propose an extended 2HDM with Q 6 × Z 4 × Z 2 symmetry that can interpret the SM fermion mass hierarchy and their mixing patterns with the Dirac CP phase in the framework of the type-I seesaw mechanism. The smallness of neutrino masses is obtained via the Type-I seesaw mechanism. Both normal and inverted neutrino mass hierarchies are consistent with the experimental data on the lepton and quark masses and mixing patterns. The prediction for the Dirac phase is δ CP ∈ (1.50, 1.82)π for normal ordering and δ CP ∈ (1.50, 1.80)π for inverted ordering that includes its experimentally maximum value. The sum of neutrino masses is predicted to be m i ∈ (58.50, 60.50) meV for normal ordering and m i ∈ (98.50, 101.00) meV for inverted ordering which are well consistent with all the recent limits. In addition, the predictions for the effective neutrino masses are m ee ∈ (3.70, 3.90)meV for normal ordering and m ee ∈ (48.00, 49.40) meV for inverted ordering which are in
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