Simple and predictive model for quark and lepton masses

A model is proposed which predicts that $m_t$ is large, that one family (e, u, and d) has only radiatively generated—and hence small—masses, and that at the unification scale $m_{\tau }^0$≃$m_b^0$ but $m_{\mu }^0$≠$m_s^0$ and $m_e^0$≠$m_d^0$. An essential feature of the model is a close connection between the pattern of breaking of unified gauge symmetry at large scales and the pattern of fermion masses at low scales, which gives a group-theoretical understanding of many features of the quark and lepton masses.