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. RI ANTONELLI, ANTONELLA/C-6238-2011; Jones, Roger/H-5578-2011; Passalacqua, Luca/F-5127-2011; Murtas, Fabrizio/B-5729-2012; O'Shea, Val/G-1279-2010
Measurement of the Tau Polarisation at LEP
TRICOMI, Alessia Rita;
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. RI ANTONELLI, ANTONELLA/C-6238-2011; Jones, Roger/H-5578-2011; Passalacqua, Luca/F-5127-2011; Murtas, Fabrizio/B-5729-2012; O'Shea, Val/G-1279-2010I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
