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It is shown that almost all features of the quark and lepton masses can be satisfactorily and simply explained without family symmetry, including the threefold mass hierarchy among the generations, and the relations m_τ⁰mb⁰, m_μ⁰3mₛ⁰, mₑ⁰1/3md⁰, mᵤ⁰/mₜ⁰md⁰/mb⁰, tanθc√md⁰mₛ⁰, Vcb√mₛ⁰/mb⁰, and Vub~VcbVᵤₛ. Various aspects of the group theory of SO(10) play an essential role in explaining these relations. There are distinctive and testable predictions for tanβ and the neutrino mixing angles.
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Babu et al. (1995) studied this question.
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