Tau polarization at DELPHI

Abstract This report describes a precise measurement of tau lepton polarization using about 110 pb −1 of data collected by DELPHI experiment in 1993–95 at and near the Z pole. In addition, a measurement of tau polarization well above the Z peak is presented for the first time. The results are based on 430 pb −1 of DELPHI data collected in 1997–99 at anaverage LEP energy of about 197 GeV.