Measurement of the τ lifetime from Belle

The lifetime of the τ-lepton is measured using the process e+e−→τ+τ−, where both τ-leptons decay to 3πν. The preliminary result based on 711 fb−1 of data collected on the ϒ(4S) resonance and in the nearby continuum is ττ=(290.18±0.54(stat.)±0.33(syst.))×10−15s.