2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/44303We present a new mechanism to explain naturally and through a common flavour symmetry the mildly hierarchical neutrino masses with large mixings and the hierarchical Yukawa matrices with small mixing angles. Although this mechanism is not linked to a particular flavour symmertry, it is particularly simple in the framework of a SU(3) flavour symmetry. In this model, we obtain exactly maximal atmospheric mixing, large although not maximal solar mixing and a normal neutrino hierarchy. All neutrino parameters are basically fixed. For instance, we predict that the angle $θ_{13}$ comes entirely from the charged lepton sector and, using the difference of the solar angle from maximality, we can fix the mass of lightest neutrino.4 pages, no figures. Wrong sentence below Eq(4) corrected, example replaced Several typos corrected. Results and conclusions completely unchangedHigh Energy Physics - Phenomenologytext