LEP summary on weak dipole moments of the τ lepton

Abstract

LEP measurements of the weak electric dipole moment d w τ and the weak anomalous magnetic dipole moment a ω τ of the τ lepton are reviewed and the search for CP violation in the production of τ pairs on the Z peak is discussed. Two methods of the measurement of the weak dipole moments based on the analysis of the transverse and normal components of single τ polarisation (azimuthal asymmetries) and spin-spin correlations (optimal observables) are discussed. Averaging the LEP measurements, upper limits on the weak electric dipole moment of the τ lepton are obtained.