Up quark masses from down quark masses

Abstract

The quark and charged lepton masses and the angles and phase of the CKM mixing matrix are nicely reproduced in a model which assumes SU ( 3 ) ⊗ SU ( 3 ) flavor symmetry broken by the v.e.v.'s of fields in its bi-fundamental representation. The relations among the quark mass eigenvalues, m u / m c ≈ m c / m t ≈ m d 2 / m s 2 ≈ m s 2 / m b 2 ≈ Λ GUT 2 / M Pl 2 , follow from the broken flavor symmetry. Large tan β is required which also provides the best fits to data for the obtained textures. Lepton–quark grandunification with a field that breaks both SU ( 5 ) and the flavor group correctly extends the predictions to the charged lepton masses. The seesaw extension of the model to the neutrino sector predicts a Majorana mass matrix quadratically hierarchical as compared to the neutrino Dirac mass matrix, naturally yielding large mixings and low mass hierarchy for neutrinos.