The polarization of tau leptons produced in the reaction e+ e- at the Z resonance has been measured using the tau decay modes e nu_e nu_tau, mu nu_mu nu_tau, pi nu_tau, rho nu_tau and a_1 nu_tau. The mean value obtained is P_tau = -0.152 +/- 0.045, indicating that parity is violated in the neutral current process e+e- ->tau+tau-. The result corresponds to a ratio of the neutral current vector and axial vector coupling constants of the tau lepton g_nu_tau((M_Z) ^2)/gAtau((M_Z)^2) = 0.076 +/- 0.023 and a value of the electroweak mixing parameter sin^2(teta_W((M_Z)^ 2))) = 0.2302 +/- 0.0058.
Measurement of the polarization of tau leptons produced in Z decays
BATIGNANI, GIOVANNI;CIOCCI, MARIA AGNESE;FERRANTE, ISIDORO;FIDECARO, FRANCESCO;FORTI, FRANCESCO;GIORGI, MARCELLO;MESSINEO, ALBERTO MARIA;TONELLI, GUIDO EMILIO;TRIGGIANI, GIUSEPPE;
1991-01-01
Abstract
The polarization of tau leptons produced in the reaction e+ e- at the Z resonance has been measured using the tau decay modes e nu_e nu_tau, mu nu_mu nu_tau, pi nu_tau, rho nu_tau and a_1 nu_tau. The mean value obtained is P_tau = -0.152 +/- 0.045, indicating that parity is violated in the neutral current process e+e- ->tau+tau-. The result corresponds to a ratio of the neutral current vector and axial vector coupling constants of the tau lepton g_nu_tau((M_Z) ^2)/gAtau((M_Z)^2) = 0.076 +/- 0.023 and a value of the electroweak mixing parameter sin^2(teta_W((M_Z)^ 2))) = 0.2302 +/- 0.0058.File in questo prodotto:
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