Neutrino masses and gauged U(1)ℓ lepton number

Abstract

Abstract We investigate the tree-level neutrino mass generation in the gauged U(1) ℓ lepton model recently proposed by us [1]. With the addition of one Standard Model(SM) singlet, ϕ 1(Y = 0, ℓ = 1), and one SM triplet scalar, T (Y = −1, ℓ = 0), realistic lepton masses can be accommodated. The resulting magnitude of neutrino mass is given by ∼ v t 3 /v L 2 , where v t and v L are the vacuum expectation values of T and ϕ 1, respectively, and it is automatically of the inverse see-saw type. Since v L is the lepton number violation scale we take it to be high, i.e. O ≳ (TeV). Moreover, the induced lepton flavor violating processes and the phenomenology of the peculiar triplet are studied. An interesting bound, 0.1 ≲ v t ≲ 24.1 GeV, is obtained when taking into account the neutrino mass generation, Br(μ → eγ), and the limits from oblique parameters, ΔS and ΔT. Collider phenomenology of the SM triplets is also discussed.