Prog. Theor. Phys. Vol. 70 No. 6 (1983) pp. 1624-1635
Electroweak Gauge Models with Broken Generation Symmetry
Atomic Energy Research Institute and Department of Physics, College of Science and Technology, Nihon University, Tokyo 101
(Received June 3, 1983)
As an approach to the so-called generation or family problem in the framework of the minimal SU (2) ×U (1) electroweak gauge model with n lepton and n quark generations, we require that the whole Lagrangian be invariant under the symmetric group Sn with respect to generation. Since, with the standard Higgs doublet φ only, one necessarily encounters degeneracy in fermion masses if n ≥3, in contradiction to observation, we introduce, in addition, n Higgs doublets φi which carry the generation index. It is shown that no more than six generations can be incorporated into the model and that no more than three generations can mix weakly. We also investigate the case in which there are only n-1 Higgs doublets transforming as an (n-1)-plet under Sn.
DOI : 10.1143/PTP.70.1624
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