Vectorlike leptons: Muon g - 2 anomaly, lepton flavor violation, Higgs boson decays, and lepton nonuniversality

摘要

In this paper, we consider the Standard Model (SM) with one family of vectorlike (VL) leptons, which couple to all three families of the SM leptons. We study the constraints on this model coming from the heavy-charged lepton mass bound, electroweak precision data, the muon anomalous magnetic moment, lepton flavor violation, Higgs boson decay constraints, and a recently measured lepton nonuniversality observable, R_(K_(*0)) , along with R_K. We find that the strongest constraints are coming from the muon g - 2, R_(μμ) = Γ(h → μμ)/Γ(h → μμ)_(SM), R_(γγ) and BR(μ → eγ). Although VL leptons couple to all three families of the SM leptons, the ratio of electron-VL to muon-VL coupling is constrained to be <λ_e/λ_μ> approx< 10~(-4). We also find that this model cannot fit the lepton nonuniversality discrepancies.