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Fermion masses in E_6 grand unification with family permutation symmetries

Francesco Caravaglios·Stefano Morisi
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Abstract

Neutrino masses have been extensively studied in the context of discrete symmetries. A family permutation symmetry easily explains all neutrino oscillations and their mixing angles. However it is not obvious the embedding of such symmetry in a grand unified theory where all fermions live in the same representation. We show that it is possible to embed such a horizontal discrete symmetry in a grand unified theory. We discuss an E_6 GUT model as in [1], but differently from [1], we take the SM Higgs doublet in the 351' to have (+3,+5) charges with respect the additional U(1)_r X U(1)_t. This choice makes possible two different horizontal symmetry breaking patterns and a distinction between neutrinos and the rest of matter fermions.

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Francesco Caravaglios, Stefano Morisi. 2005-10-24. Fermion masses in E_6 grand unification with family permutation symmetries. https://arxiv.org/abs/hep-ph/0510321

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