Article ID Journal Published Year Pages File Type
9861391 Physics Letters B 2005 7 Pages PDF
Abstract
The leptonic mixing angle θ13 is known to be small. If it is indeed tiny, the simplest explanation is that charged leptons mix only in the μ-τ sector and neutrinos only in the 1-2 sector. We show that this pattern may be explained by the discrete symmetry Z2×Z2 of a complete Lagrangian, which has 2 Higgs doublets and 2 Higgs triplets (or 2 heavy right-handed singlet neutrinos). In the case of Higgs triplets, the Majorana neutrino masses are arbitrary, whereas in the case of heavy singlet neutrinos, an inverted hierarchy is predicted. Lepton-flavor-violation effects, present only in the μ-τ sector, are analyzed in detail: the LFV τ-decay rates are predicted below the present bounds by a few orders of magnitude, whereas LFV Higgs decays could allow for a direct test of the model.
Related Topics
Physical Sciences and Engineering Physics and Astronomy Nuclear and High Energy Physics
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