Contribution Of Flavorful Vector-like Leptons To The Lepton Flavor Violating Decays Z→l_il_j

Searching for new physics(NP)beyond the Standard Model(SM)is an important task in current particle physics.In the Standard Model,the branching ratio of lepton flavor violating(LFV)decay is very small and cannot reach the experimental observable level.Therefore,if lepton flavor violating processes is discovered in the experiment,it will be indirect evidence of the existence of new physics.Currently,many new physical models are contributing to lepton flavour violating contributions,such as the Supersymmetric standard model,the Zee model and the VLS model.The VLS model predicts the existence of vector-like leptons(VLLs)and new scalars,which would contribute to the lepton flavor violating decays Z→lilj.In this thesis,we calculate the contributions of VLLs to the lepton flavor violating decays Z→lilj.Our numerical results show that it will be possible to detect the contributions of the singlet VLLs to Z→τμ and Z→τe at the future electron positron collider(FCC-ee or CEPC).This will help to detect the physical signals of such kind models on the FCC-ee or CEPC in the future.