Published: 2005
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The polarization of [tau] leptons produced in the reaction e[sup +]e[sup [minus]] [yields] [tau][sup +][tau][sup [minus]] near the peak of the Z[degree] resonance has been measured using a sample of 24904 [tau][sup +][tau][sup [minus]] events, with an estimated background of 1.5%. We have selected 4562 [tau] [yields] e[nu][bar [nu]] 2218 [tau] [yields] [pi][nu] and 5133 [tau] [yields] [rho][nu] candidates. The mean value obtained is P[sub [tau]] = [minus]0.176 [plus-minus] 0.029. This corresponds to a ratio of the neutral current vector to the axial-vector coupling constants of the [tau] lepton of g[sub V][sup [tau]]/g[sub A][sup [tau]] = 0.088 [plus-minus] 0.014. This leads to a value of the electroweak mixing angle of sin[sup 2][theta][sub W] = 0.2280 [plus-minus] 0.0036. This result is in good agreement with previous measurements of the weak mixing angle from the study of the Z[degree] lineshape and the forward-backward asymmetries in the processes Z[degree] [yields] l[sup +]l[sup [minus]] and Z[degree] [yields] q[bar q].
