A Measurement of the Michel Parameters in Leptonic Decays of the Tau

We have measured the spectral shape Michel parameters ρ and η using leptonic decays of the τ, recorded by the CLEO II detector. Assuming e-μ universality in the vectorlike couplings, we find ρeμ = 0.735 ± 0.013 ± 0.008 and ηeμ = 20.015 ± 0.061 ± 0.062, where the first error is statistical and the second systematic. We also present measurements for the parameters for e and μ final states separately