HAL : in2p3-00000023, version 1
 Physics Letters B 429 (1998) 387-398
 Measurement of $\tau$ Polarisation at LEP
 L3 Collaboration(s)
 (1998)
 Using the data collected with the L3 detector at LEP between 1990 and 1995, corresponding to an integrated luminosity of 149 pb$^{-1}$, the $\tau$ longitudinal polarisation has been measured as a function of the production polar angle using the $\tau$ decays \thad\ ($\rm h = \pi, \rho, \aone$) and \tlep\ ($\rm \ell = e, \mu$). From this measurement the quantities ×l~and \at, which depend on the couplings of the electron and the $\tau$ to the Z, are determined to be $æl = 0.1678 \pm 0.0127 \pm 0.0030$ and $\at = 0.1476 \pm 0.0088 \pm 0.0062$, consistent with the hypothesis of e--$\tau$ universality. Under this assumption a value of $\al = 0.1540 \pm 0.0074 \pm 0.0044$ is obtained, yielding the value of the effective weak mixing angle $\swsqb = 0.2306 \pm 0.0011$.
 équipe(s) de recherche : CMS
 Thème(s) : Physique/Physique des Hautes Energies - Expérience
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 in2p3-00000023, version 1 http://hal.in2p3.fr/in2p3-00000023 oai:hal.in2p3.fr:in2p3-00000023 Contributeur : Sylvie Florès <> Soumis le : Jeudi 5 Novembre 1998, 12:13:25 Dernière modification le : Mercredi 20 Avril 2005, 16:20:53