Tau polarisation measurement at LEP

The measurement of the tau polarisation at LEP has been performed by the four experiments. New preliminary measurements from ALEPH and DELPHI allow to reach a very good precision. The results on A/sub tau / and A/sub e/ show good consistency among the four LEP experiments. The ratio of the tau to electron vector couplings verifies the lepton universality in the neutral current. In the framework of the standard model, the effective electroweak mixing angle is measured to be sin /sup 2/ theta /sub W/=0.23176+or-0.00043. (5 refs).