Electron and muon g − 2, radiative neutrino mass, and ℓ′ → ℓγ in a U(1)e−μ model

Abstract A nonconventional U ( 1 ) e − μ gauge model is proposed to explain the observed neutrino masses and the unexpected anomalous magnetic moments of the electron and muon (lepton g − 2 ), where for suppressing the neutrino coupling to Z ′ gauge boson, only the right-handed electron and muon in the standard model carry the U ( 1 ) e − μ charge. Although the light lepton masses are suppressed when the gauge symmetry is spontaneously broken, they can be generated through the Yukawa couplings to newly introduced particles, such as vector-like lepton doublets and singlets, and scalar singlets. It is found that the same Yukawa couplings combined with the new scalar couplings to the Higgs can induce the radiative lepton-flavor violation processes l ′ → l γ and lepton g − 2 , where the lepton g − 2 is proportional to m l . When Majorana fermions and a scalar singlet are further added into the model, the active neutrinos can obtain masses via the radiative seesaw mechanism. When the bounds from the m e and m μ and the neutrino data are satisfied, we find that the electron g − 2 can reach an order of − 10 − 12 , and the muon g − 2 can be an order of 10 − 9 . In addition, when the μ → e γ decay is suppressed, the resulting branching ratio for τ → e γ can be of O ( 10 − 8 ) , and that for τ → μ γ can be as large as the current upper limit.