Up Quark Masses from Down Quark Masses


Abstract in English

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)xSU(3) flavour 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 approx m_c/m_t approx m^2_d/m^2_s approx m^2_s/m^2_b approx Lambda^2_{GUT}/M^2_{Pl}, follow from the broken flavour symmetry. Large tan(beta) 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 flavour 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.

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