2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/42785Under the assumptions that 1) the quark/lepton mass matrices take Froggatt-Nielsen's factorized power form λ^{ψ_i+ψ_j} with anomalous U(1) charges ψ_i, and 2) the U(1) charges ψ_i respect the SU(5) GUT structure, we show that the quark mass data and the mass-squared difference ratio of solar and atmospheric neutrinos, as inputs, necessarily imply that both the 1-2 and 2-3 mixings in the MNS matrix U_{MNS} are large. This analysis also gives a prediction that U_{e3}\equiv (U_{MNS})_{13} is of order λ\sim (0.1 - 0.5). We also add an argument that E_6 GUT is favored.4 pages, RevTeXHigh Energy Physics - Phenomenologytext