Bounding the magnetic and electric dipole moments of ντ from the process e+e-→ννγ in E6 superstring models

We obtain bounds on the anomalous magnetic and electric dipole moments of the tau-neutrino through the reaction e(+)e(-)->nu nu gamma at the Z(1)-pole in the framework of a Left-Right symmetric model and a class of E-6 inspired models with an additional neutral vector boson Z(theta). We use the data collected by the L3 Collaboration at LEP. For the parameters of the E-6 model we consider the mixing angle theta(E6)=37.8 degrees and M-Z theta=7M(Z1). We find that our bounds are of the same order of magnitude as those obtained in other extensions of the standard model.