Measurements of the Leptonic Branching Ratios with OPAL

The branching ratio of the τ¯→e¯ v¯ _ev_τ decay and the radiative tau decay τ→ u¯ v¯ _uv_τγ have been measured with the OPAL detector at LEP. A branching ratio of 0.1778±0.0010±0.0009 was obtained for the τ¯→e¯ v¯ _ev_τ decay mode and (3.0 ± 0.4 ± 0.5) × 10 ^-3 for the τ¯→ u¯ v¯ _uv_τγ decay mode for photon energies above 20 MeV in the tau rest frame.