Flavor Dependent $U(1)$ Symmetric Zee Model with a Vector-like Lepton

Toshinori Matsui; Takaaki Nomura; Kei Yagyu

doi:10.1016/j.nuclphysb.2021.115523

paper

Flavor Dependent $U (1)$ Symmetric Zee Model with a Vector-like Lepton

arXiv:2102.09247 · doi:10.1016/j.nuclphysb.2021.115523

Abstract

We extend the Zee model by introducing a vector-like lepton doublet and a flavor dependent global $U (1)$ symmetry. Flavor changing neutral currents in the quark sector can be naturally forbidden at tree level due to the $U (1)$ symmetry, while sufficient amount of lepton flavor violation is provided to explain current neutrino oscillation data. In our model, additional sources of CP-violation appear in the lepton sector, but their contribution to electric dipole moments is much smaller than current experimental bounds due to the Yukawa structure constrained by the $U (1)$ symmetry. We find that there is a parameter region where the strongly first order electroweak phase transition can be realized, which is necessary for the successful scenario of the electroweak baryogenesis in addition to new CP-violating phases. In the benchmark points satisfying neutrino data, lepton flavor violation data and the strongly first order phase transition, we show that an additional CP-even Higgs boson $H$ mainly decays into a lighter CP-odd Higgs boson $A$ , i.e., $H \to A Z$ or $H \to AA$ with a characteristic pattern of lepton flavor violating decays of $A$ .

40 pages, 23 figures, version accepted in Nuclear Physics B

Flavor Dependent U(1) Symmetric Zee Model with a Vector-like Lepton

Abstract

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Flavor Dependent $U (1)$ Symmetric Zee Model with a Vector-like Lepton