With a data sample of 86 000 Z --> tau(+)tau>(-)(gamma) events collected in 1990 through 1993 we have measured the polarization of tau-leptons as a function of the production polar angle using the following 1-prong tau decay modes: tau(-) --> e(-)<(nu)over bar>(e) nu(tau),tau(-) --> mu(-)<(nu)over bar>(mu)nu(tau), tau(-) --> pi(-)(K-)nu(tau),tau(-) --> rho(-)nu(tau) and tau(-) --> a(1)(-)nu(tau). We obtain for the ratio of vector to axial-vector weak neutral couplings for electrons gVe/gAe = 0.0791 +/- 0.0099(stat) +/- 0.0025(syst) and taus gV tau/gA tau = 0.0752 +/- 0.0063(stat) +/- 0.0045(syst) consistent with the hypothesis of e - tau universality. Assuming universality of the e - tau neutral current we determine the effective electroweak mixing angle to be sin(2) theta(W)(eff) = 0.2309 +/- 0.0016.

A measurement of τ polarization at LEP

MONACO, Vincenzo;
1994-01-01

Abstract

With a data sample of 86 000 Z --> tau(+)tau>(-)(gamma) events collected in 1990 through 1993 we have measured the polarization of tau-leptons as a function of the production polar angle using the following 1-prong tau decay modes: tau(-) --> e(-)<(nu)over bar>(e) nu(tau),tau(-) --> mu(-)<(nu)over bar>(mu)nu(tau), tau(-) --> pi(-)(K-)nu(tau),tau(-) --> rho(-)nu(tau) and tau(-) --> a(1)(-)nu(tau). We obtain for the ratio of vector to axial-vector weak neutral couplings for electrons gVe/gAe = 0.0791 +/- 0.0099(stat) +/- 0.0025(syst) and taus gV tau/gA tau = 0.0752 +/- 0.0063(stat) +/- 0.0045(syst) consistent with the hypothesis of e - tau universality. Assuming universality of the e - tau neutral current we determine the effective electroweak mixing angle to be sin(2) theta(W)(eff) = 0.2309 +/- 0.0016.
1994
341
245
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FERMION-PAIR PRODUCTION; HIGH-ENERGY LEPTON
M. Acciarri;A. Adam;O. Adriani;M. Aguilar-Benitez;S. Ahlen;J. Alcaraz;A. Aloisio;G. Alverson;M.G. Alviggi;G. Ambrosi;Q. An;H. Anderhub;A.L...espandi
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2318/124947
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