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Measurement of the Michel parameters and the \(\nu_\tau\) helicity in \(\tau\) lepton decays

  • The ALEPH Collaboration
  • A. Heister et al.
Experimental physics

Abstract.

A measurement of the Michel parameters and the average \(\nu_\tau\) helicity in \(\tau\) lepton decays is described. The data was collected with the ALEPH detector at LEP during the years 1991 to 1995. A total integrated luminosity of 155 \(\text{pb}^{-1}\) is analysed. The Michel parameters \(\rho_l, \xi_l, (\xi\delta)_l (l=e,\mu)\), and \(\eta_\mu\) are determined for the leptonic decays, and the chirality parameters \(\xi_\pi, \xi_\rho\), and \(\xi_{a_1}\) for the hadronic final states. Under the assumptions of e-\(\mu\) universality and \(\xi_\pi=\xi_\rho=\xi_{a_1}\), the values \(\rho_l=0.742\pm 0.016, \eta_l=0.012\pm 0.026, (\xi\delta)_l=0.776\pm 0.051,\xi_l=0.986\pm0.074\), and \(\xi_h=0.992\pm 0.011\) are obtained. No significant deviation is observed from the Standard Model assumption of the V-A structure of the charged weak interaction.

Keywords

Weak Interaction Model Assumption Integrate Luminosity Leptonic Decay Hadronic Final State 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer-Verlag Berlin Heidelberg / Società Italiana di Fisica 2001

Authors and Affiliations

  • The ALEPH Collaboration
  • A. Heister et al.
    • 1
  1. 1.Physikalisches Institut das RWTH-Aachen, 52056 Aachen, GermanyDE

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