LIMITS ON THE ELECTROMAGNETIC AND WEAK DIPOLE MOMENTS OF THE TAU-LEPTON IN E6 SUPERSTRING MODELS

Abstract

We obtain limits on the electromagnetic and weak dipole moments of the tau-lepton in the framework of a left–right symmetric model (LRSM) and a class of E6 inspired models with an additional neutral vector boson Zθ. Using as an input the data obtained by the L3 and OPAL collaborations for the reaction e+e- → τ+τ-γ, we get a stringent limit on the LRSM mixing angle ϕ, -1.66 × 10-3 < ϕ<1.22×10-3, which in turn induces bounds on the tau weak dipole moments which are consistent with the bounds obtained recently by the DELPHI and ALEPH collaborations from the reaction e+e-→τ+τ-. We also get similar bounds for the weak dipole moments of the tau lepton in the framework of E6 superstring models.