TY - JOUR

T1 - Precision neutral current asymmetry parameter measurements from the Tau polarization at LEP

AU - Abbiendi, G

AU - Ashby, Shaun

AU - Bloodworth, Ian

AU - Bright-Thomas, Paul

AU - Charlton, David

AU - Hawkes, Christopher

AU - Homer, Roger

AU - Jovanovic, Predrag

AU - Lloyd, Alun

AU - McMahon, Thomas

AU - O'Neale, Stephen

AU - Talbot, Scott

AU - Watson, Miriam

AU - Watkins, Peter

AU - Watson, Alan

AU - Watson, Nigel

AU - Wilson, John

PY - 2001/6/1

Y1 - 2001/6/1

N2 - Measurements of the tau lepton polarization and forward-backward polarization asymmetry near the Z(0) resonance using the OPAL detector are described. The measurements are based on analyses of tau -->e nu (e)nu (tau), tau --> mu nu (mu)nu (tau), tau --> pi nu (tau), tau --> rho nu (tau) and tau -->a(1)nu (tau) decays from a sample of 144,810 e(+) e(-) --> tau (+) tau (-) candidates corresponding to an integrated luminosity of 151 pb(-1). Assuming that the tau lepton decays according to V-A theory, we measure the average tau polarization near roots = M-z to be = (-14.10 +/- 0.73 +/-0.55)% and the tau polarization forward-backward asymmetry to be A(pol)(FB) = (-10.55 +/-0.76 +/-0.25)%, where the first error is statistical and the second systematic. Taking into account the small effects of the photon propagator, photon-Z(0) interference and photonic radiative corrections, these results can be expressed in terms of the lepton neutral current asymmetry parameters: A(tau) = 0.1456 +/- 0.0076 +/- 0.0057 A(e) = 0.1454 +/- 0.0108 +/- 0.0036 These measurements are consistent with the hypothesis of lepton universality and combine to give A(t) = 0.1455 +/-0.0073. Within the context of the Standard Model this combined result corresponds to = 0.23172 +/-0.00092. Combing these results with those from the other OPAL neutral current measurements yields a value of = 0.23211 +/-0.00068.

AB - Measurements of the tau lepton polarization and forward-backward polarization asymmetry near the Z(0) resonance using the OPAL detector are described. The measurements are based on analyses of tau -->e nu (e)nu (tau), tau --> mu nu (mu)nu (tau), tau --> pi nu (tau), tau --> rho nu (tau) and tau -->a(1)nu (tau) decays from a sample of 144,810 e(+) e(-) --> tau (+) tau (-) candidates corresponding to an integrated luminosity of 151 pb(-1). Assuming that the tau lepton decays according to V-A theory, we measure the average tau polarization near roots = M-z to be = (-14.10 +/- 0.73 +/-0.55)% and the tau polarization forward-backward asymmetry to be A(pol)(FB) = (-10.55 +/-0.76 +/-0.25)%, where the first error is statistical and the second systematic. Taking into account the small effects of the photon propagator, photon-Z(0) interference and photonic radiative corrections, these results can be expressed in terms of the lepton neutral current asymmetry parameters: A(tau) = 0.1456 +/- 0.0076 +/- 0.0057 A(e) = 0.1454 +/- 0.0108 +/- 0.0036 These measurements are consistent with the hypothesis of lepton universality and combine to give A(t) = 0.1455 +/-0.0073. Within the context of the Standard Model this combined result corresponds to = 0.23172 +/-0.00092. Combing these results with those from the other OPAL neutral current measurements yields a value of = 0.23211 +/-0.00068.

U2 - 10.1007/s100520100714

DO - 10.1007/s100520100714

M3 - Article

VL - 21

SP - 1

EP - 21

JO - European Physical Journal C

JF - European Physical Journal C

IS - 1

ER -