2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/180552Realistic quark masses and mixing angles are obtained applying the successful $A_4$ family symmetry for leptons, motivated by the quark-lepton assignments of SU(5). The $A_4$ symmetry is suitable to give tri-bimaximal neutrino mixing matrix which is consistent with current experimental data. We study new scenario for the quark sector with the $A_4$ symmetry.16 pages, 2 figures, Talk given at International Workshop on Neutrino Masses and Mixings, Shizuoka, Japan, 17-19 December 2006High Energy Physics - Phenomenologytext