Based on 520 000 fermion pairs accumulated during the first three years of data collection by the ALEPH detector at LEP, updated values of the resonance parameters of the Z are determined to be MZ=(91.187±0.009) GeV, ΓZ=(2.501±0.012) GeV, σhad 0=(41.60±0.27) nb, and Rℓ=20.78±0.13. The corresponding number of light neutrino species is Nν=2.97±0.05. The forward-backward asymmetry in lepton-pair decays is used to determine the ratio of vector to axial-vector couplings of leptons:gV 2(MZ 2)/gA 2(MZ 2)=0.0052±0.0016. Combining this with ALEPH measurements of the b and c quark asymmetries and τ polarization gives sin2θW eff=0.2326±0.0013. Assuming the minimal Standard Model, and including measurements of MW/MZ from p {Mathematical expression} colliders and neutrino-nucleon scattering, the mass of the top quark is {Mathematical expression} GeV.

Buskulic, D., Decamp, D., Goy, C., Lees, J., Minard, M., Mours, B., et al. (1993). Update of electroweak parameters from Z decays. ZEITSCHRIFT FÜR PHYSIK. C, PARTICLES AND FIELDS, 60(1), 71-81 [10.1007/BF01650432].

Update of electroweak parameters from Z decays

CARPINELLI, Massimo;
1993

Abstract

Based on 520 000 fermion pairs accumulated during the first three years of data collection by the ALEPH detector at LEP, updated values of the resonance parameters of the Z are determined to be MZ=(91.187±0.009) GeV, ΓZ=(2.501±0.012) GeV, σhad 0=(41.60±0.27) nb, and Rℓ=20.78±0.13. The corresponding number of light neutrino species is Nν=2.97±0.05. The forward-backward asymmetry in lepton-pair decays is used to determine the ratio of vector to axial-vector couplings of leptons:gV 2(MZ 2)/gA 2(MZ 2)=0.0052±0.0016. Combining this with ALEPH measurements of the b and c quark asymmetries and τ polarization gives sin2θW eff=0.2326±0.0013. Assuming the minimal Standard Model, and including measurements of MW/MZ from p {Mathematical expression} colliders and neutrino-nucleon scattering, the mass of the top quark is {Mathematical expression} GeV.
Articolo in rivista - Articolo scientifico
Physics
English
1993
60
1
71
81
none
Buskulic, D., Decamp, D., Goy, C., Lees, J., Minard, M., Mours, B., et al. (1993). Update of electroweak parameters from Z decays. ZEITSCHRIFT FÜR PHYSIK. C, PARTICLES AND FIELDS, 60(1), 71-81 [10.1007/BF01650432].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/390410
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