par Abreu, Pedro;Bertrand, Daniel 
;Bricman, Charles ;Cao, Futian;De Boeck, Hugo;De Brabandere, S.;De Clercq, Catherine;Grard, Fernand ;Herquet, Philippe ;Huet, Kathy;Lefebure, Véronique ;Lemonne, Jacques ;Tomaradze, A.;Vander Velde, Catherine ;Van Doninck, Walter;Verbeure, F;Wickens, John H. ; [et al.]
Référence Zeitschrift für Physik. C, Particles and fields, 67, 2, page (183-201)
Publication Publié, 1995-06
;Bricman, Charles ;Cao, Futian;De Boeck, Hugo;De Brabandere, S.;De Clercq, Catherine;Grard, Fernand ;Herquet, Philippe ;Huet, Kathy;Lefebure, Véronique ;Lemonne, Jacques ;Tomaradze, A.;Vander Velde, Catherine ;Van Doninck, Walter;Verbeure, F;Wickens, John H. ; [et al.]Référence Zeitschrift für Physik. C, Particles and fields, 67, 2, page (183-201)
Publication Publié, 1995-06
Article révisé par les pairs
| Résumé : | A sample of Z0→τ+τ- events observed in the DELPHI detector at LEP in 1991 and 1992 is analysed to measure the τ polarisation in the exclusive decay channels {Mathematical expression}, {Mathematical expression}, πν, ρν and a1ν. The τ polarisation is also measured with an inclusive hadronic analysis which benefits from a higher efficiency and a better systematic precision than the use of the exclusive decay modes. The results have been combined with those published on the 1990 data. A measurement of the τ polarisation as a function of production angle yields the values for the mean τ polarisation 〈P〉τ=-0.148±0.022 and for the Z0 polarisation PZ=-0.136±0.027. These results are used to determine the ratio of vector to axial-vector effective couplings for taus {Mathematical expression}, and for electrons {Mathematical expression}, compatible with e-τ universality. With the assumption of lepton universality, the ratio of vector to axial-vector effective couplings for leptons {Mathematical expression} is obtained, implying a value of the effective weak mixing angle sin2θefflept=0.2320±0.0021 . © 1995 Springer-Verlag. |
