The Tauonic Branching Ratio of UPSILON(1S)

We have studied the leptonic decay of the Upsilon (1S) resonance into tau pairs using the CLEO II detector. A clean sample of tau pair events is identified via the 1-vs.-1 topology where exactly one of the charged particles is an identified electron. We find B(Upsilon (1S) to tau^+ tau^-) = (2.61 +/- 0.12_sp{-0.13}{+0.09}) %. The result is consistent with expectations from lepton universality.