Effects of anomalous couplings of the tau lepton

The dimension-six CP-conserving SU L (2) × U Y (1) invariant operators involving the tau lepton are studied. It leads to the new physics effects to the lepton flavor violation (LFV) and lepton flavor-changing neutral current (FCNC). With the available experimental data on the decays Z → τ + + τ − , Z → µ + + µ − and µ − → e − + γ, the constraints on parameters of the effective lagrangian can be given. According to such constraints, the branching ratio of the decay Z → µ ± + τ ∓ could reach to 10 −6 − 10 −7. The size of the LFV effects depends crucially on the dynamics of the lepton mass generation. Assuming the lepton mass matrices in the form of a Fritzsch ansatz, we point out that the experiment on µ → eγ will put stronger limits on the anomalous magnitic and electric dipole moments of the tau lepton than obtained by Escribano and Massó.