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

A nonconventional U(1)(e)(-mu) 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)(-mu) 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 gamma and lepton g - 2, where the lepton g - 2 is proportional to inf. 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(mu) 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 mu -> e gamma decay is suppressed, the resulting branching ratio for tau -> e gamma can be of O(10(-8)), and that for tau -> mu gamma can be as large as the current upper limit. (C) 2021 The Authors. Published by Elsevier B.V.

Automated summary

The proposed nonconventional U(1)(e)(-mu) gauge model provides an explanation for the observed neutrino masses and the unexpected anomalous magnetic moments of the electron and muon (lepton g - 2). By introducing new particles and coupling relationships, light lepton masses can be generated. Further addition of Majorana fermions and a scalar singlet can help active neutrinos obtain masses through the radiative seesaw mechanism.