Flavorful vector-like leptons and the lepton-flavor-violating decays Z → lilj

Abstract

Abstract The singlet and doublet VLS models are one kind of interesting new physics scenarios, which predict the existence of the SU(2) L singlet and doublet vector-like leptons (VLLs), respectively. Taking into account the constraints on these VLS models, we investigate their contributions to the LFV decays . Our numerical results show that, for the singlet VLS model, the values of the branching ratios and can be larger than in a wide range of the parameter space, which might be detected by CEPC/FCC-ee in the near future.