Journal article

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

G Abbiendi, C Ainsley, PF Akesson, G Alexander, J Allison, G Anagnostou, KJ Anderson, S Arcelli, S Asai, D Axen, G Azuelos, I Bailey, AH Ball, E Barberio, RJ Barlow, RJ Batley, T Behnke, KW Bell, G Bella, A Bellerive Show all



Measurements of the τ lepton polarization and forward-backward polarization asymmetry near the Z0 resonance using the OPAL detector are described. The measurements are based on analyses of τ → eνeντ, τ → μνμντ, τ → πντ, τ → ρντ, and τ → a1ντ decays from a sample of 144,810 e+e- → τ+τ- candidates corresponding to an integrated luminosity of 151 pb-1. Assuming that the τ lepton decays according to V-A theory, we measure the average τ polarization near √s = Mz to be 〈Pτ〉 = (-14.10 ± 0.73 ± 0.55)% and the τ polarization forward-backward asymmetry to be AFBpol = (-10.55 ± 0.76 ± 0.25)%, where the first error is statistical and the second systematic. Taking into account the small effects of the ph..

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