The Michel parameters rho, eta, xi and xi delta, the chirality parameter xi(h) and the tau polarization P-tau are measured using 32012 tau pair decays. Their values are extracted from the energy spectra of leptons and hadrons in tau(-) --> l(-)<(nu)over bar>(l) nu(tau) and tau(-) --> pi(-)nu(tau) decays, the energy and decay angular distributions in tau(-) --> rho(-)nu(tau) decays, and the correlations in the energy spectra and angular distributions of the decay products. Assuming universality in leptonic and semileptonic tau decays, the results are rho = 0.794+/-0.039+/-0.031, eta = 0.25+/-0.17+/-0.11, xi = 0.94+/-0.21+/-0.07, xi delta = 0.81+/-0.14+/-0.06, xi(h) = -0.970+/-0.053+/-0.011, and P-tau = -0.154+/-0.018+/-0.012. The measurement is in agreement with the V-A hypothesis for the weak charged current.

Measurement of the Michel parameters and the average tau neutrino helicity from tau decays in e(+)e(-)->tau(+)tau(-)

FERRONI, Fernando
1996

Abstract

The Michel parameters rho, eta, xi and xi delta, the chirality parameter xi(h) and the tau polarization P-tau are measured using 32012 tau pair decays. Their values are extracted from the energy spectra of leptons and hadrons in tau(-) --> l(-)<(nu)over bar>(l) nu(tau) and tau(-) --> pi(-)nu(tau) decays, the energy and decay angular distributions in tau(-) --> rho(-)nu(tau) decays, and the correlations in the energy spectra and angular distributions of the decay products. Assuming universality in leptonic and semileptonic tau decays, the results are rho = 0.794+/-0.039+/-0.031, eta = 0.25+/-0.17+/-0.11, xi = 0.94+/-0.21+/-0.07, xi delta = 0.81+/-0.14+/-0.06, xi(h) = -0.970+/-0.053+/-0.011, and P-tau = -0.154+/-0.018+/-0.012. The measurement is in agreement with the V-A hypothesis for the weak charged current.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.12571/2958
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