A measurement of τ polarization using the Venus detector at Tristan

Using 216 pb −1 of data collected at √ s = 58GeV, we have measured momentum distributions of τ decay particles in the decay modes, τ → eυυ¯ , τ → πν and τ → ϱν . The average τ polarization, which is derived from these momentum distributions, and its forward-backward asymmetry are obtained to be −0.012 ±0.052 and −0.018 ±0.088, respectively.