Determination of the Michel parameters and the tau neutrino helicity in tau decay

Using the CLEO II detector at the Cornell Electron Storage Ring operated at root s=10.6 GeV, we have determined the Michel parameters rho, xi and delta in tau(-/+)-->l(-/+) nu<(nu)over bar> decay as well as the tau neutrino helicity parameter h(nu tau) in tau(-/+)-->pi(-/+)pi(0) nu decay. From a data sample of 3.02x10(6) produced tau pairs we analyzed events of the topologies e(+)e(-)-->tau(+)tau(-)-->(l(+/-)nu<(nu)over bar>)(pi(-/+)pi(0) nu) and e(+)e(-)-->tau(+)tau(-)-->(pi(+/-)pi(0)<(nu)over bar>)pi(-/+)pi(0) nu). We obtain rho=0.747 rho =0.747+/-0.010+/-0.006, xi=1.007+/-0.040+/-0.015, xi delta=0.745+/-0.026+/-0.009, and h(nu tau)=-0.995+/-0.010 +/-0.003, when we have used the previously determined sign of h(nu tau) [ARGUS Collaboration, H. Albrecht et al., Z. Phys. C 58, 61 (1993); Phys. Lett. B 349, 576 (1995)]. We also present the Michel parameters as determined from the electron and muon samples separately. All results are in agreement with the standard model V-A interaction.