Ernest Ma

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The leptonic Higgs doublet model of neutrino masses is implemented with an A 4 discrete symmetry (the even permutation of 4 objects or equivalently the symmetry of the tetrahedron) which has 4 irreducible representations: 1, 1 ′ , 1 ′′ , and 3. The resulting spontaneous and soft breaking of A 4 provides a realistic model of charged-lepton masses as well as(More)
In the minimal standard electroweak gauge model, there is an effective dimension-five operator which generates neutrino masses. I show that there are three tree-level realizations of this operator. One is the canonical seesaw mechanism with a right-handed neutrino. Another is having a heavy Higgs triplet as recently proposed. The third possibility is to(More)
If the standard model of quark interactions is supplemented by a discrete A 4 symmetry (which may be relevant for the lepton sector), the spontaneous breaking of the electroweak gauge symmetry allows arbitrary quark masses, but all mixing angles are predicted to be zero. A pattern of the explicit breaking of A 4 is proposed, which results in a realistic(More)
A heavy triplet of leptons (Σ + , Σ 0 , Σ −) R per family is proposed as the possible anchor of a small seesaw neutrino mass. A new U(1) gauge symmetry is then also possible, and the associated gauge boson X may be discovered at or below the TeV scale. We discuss the phenomenology of this proposal, with and without possible constraints from the NuTeV and(More)