The polarisation of tau's produced in Z decay is measured using 160 pb(-1) of data accumulated at LEP by the ALEPH detector between 1990 and 1995. The variation of the polarisation with polar angle yields the two parameters A(e) = 0.1504 +/- 0.0068 and A(tau) = 0.1451 +/- 0.0059 which are consistent with the hypothesis of e-tau universality. Assuming universality, the value A(e-tau) = 0.1474 +/- 0.0045 is obtained from which the effective weak mixing angle sin(2) theta (eff)(W) = 0.23147 +/- 0.00057 is derived.
Measurement of the Tau Polarisation at LEP
SELVAGGI, Giovanna;NUZZO, Salvatore Vitale;DE PALMA, Mauro
2001-01-01
Abstract
The polarisation of tau's produced in Z decay is measured using 160 pb(-1) of data accumulated at LEP by the ALEPH detector between 1990 and 1995. The variation of the polarisation with polar angle yields the two parameters A(e) = 0.1504 +/- 0.0068 and A(tau) = 0.1451 +/- 0.0059 which are consistent with the hypothesis of e-tau universality. Assuming universality, the value A(e-tau) = 0.1474 +/- 0.0045 is obtained from which the effective weak mixing angle sin(2) theta (eff)(W) = 0.23147 +/- 0.00057 is derived.File in questo prodotto:
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