Determination of the Michel Parameters and the tau Neutrino Helicity in tau Decay
Using the CLEO II detector at the e{sup +}e{sup -} storage ring CESR, we have determined the Michel parameters {rho}, {zeta}, and {delta} in {tau}{sup {-+}}{nu}{bar {nu}} decay as well as the {tau} neutrino helicity parameter H{sub {nu}{sub {tau}}} in {tau}{sup {-+}}{pi}{sup 0}{nu} decay. From a data sample of 3.02 x 10{sup 6} {tau} pairs produced at {radical}s = 10.6 GeV, using events of the topology e{sup +}e{sup -} {yields} {tau}{sup +}{tau}{sup -} {yields} (l{sup {+-}}{nu}{bar {nu}})({pi}{sup {-+}}{pi}{sup 0}{nu}) and e{sup +}e{sup -} {yields} {tau}{sup +}{tau}{sup -} {yields} ({pi}{sup {+-}}{pi}{sup 0}{bar {nu}})({pi}{sup {-+}}{pi}{sup 0}{nu}), and the determined sign of h{sub {nu}{sub {tau}}} [1,2], the combined result of the three samples is: {rho} = 0.747 {+-} 0.010 {+-} 0.006, {zeta} = 1.007 {+-} 0.040 {+-} 0.015, {zeta}{delta} = 0.745 {+-}0.026 {+-}0.009, and h{sub {nu}{sub {tau}}} = -0.995 {+-} 0.010 {+-} 0.003. The results are in agreement with the Standard Model V-A interaction.
- Research Organization:
- SLAC National Accelerator Lab., Menlo Park, CA (United States)
- Sponsoring Organization:
- USDOE Office of Science (US)
- DOE Contract Number:
- AC03-76SF00515
- OSTI ID:
- 813081
- Report Number(s):
- SLAC-PUB-9780; TRN: US0303644
- Resource Relation:
- Other Information: PBD: 7 May 2003
- Country of Publication:
- United States
- Language:
- English
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