Precise Determination of the Z Resonance Parameters at LEP : Zedometry
| dc.creator | The OPAL collaboration | |
| dc.creator | Abbiendi, G. | |
| dc.date | 2000-12-06 | |
| dc.date.accessioned | 2026-07-07T12:01:34Z | |
| dc.date.available | 2026-07-07T12:01:34Z | |
| dc.description | This final analysis of hadronic and leptonic cross-sections and of leptonic forward-backward asymmetries in e+e- collisions with the OPAL detector makes use of the full LEP1 data sample comprising 161 pb^-1 of integrated luminosity and 4.5 x 10^6 selected Z decays. An interpretation of the data in terms of contributions from pure Z exchange and from Z-gamma interference allows the parameters of the Z resonance to be determined in a model-independent way. Our results are in good agreement with lepton universality and consistent with the vector and axial-vector couplings predicted in the Standard Model. A fit to the complete dataset yields the fundamental Z resonance parameters: mZ = 91.1852 +- 0.0030 GeV, GZ = 2.4948 +- 0.0041 GeV, s0h = 41.501 +- 0.055 nb, Rl = 20.823 +- 0.044, and Afb0l = 0.0145 +- 0.0017. Transforming these parameters gives a measurement of the ratio between the decay width into invisible particles and the width to a single species of charged lepton, Ginv/Gl = 5.942 +- 0.027. Attributing the entire invisible width to neutrino decays and assuming the Standard Model couplings for neutrinos, this translates into a measurement of the effective number of light neutrino species, N_nu = 2.984 +- 0.013. Interpreting the data within the context of the Standard Model allows the mass of the top quark, mt = 162 +29-16 GeV, to be determined through its influence on radiative corrections. Alternatively, utilising the direct external measurement of mt as an additional constraint leads to a measurement of the strong coupling constant and the mass of the Higgs boson: alfa_s(mZ) = 0.127 +- 0.005 and mH = 390 +750-280 GeV. | |
| dc.description | 119 pages, 26 figures, submitted to Eur. Phys. J. C | |
| dc.identifier | https://arxiv.org/abs/hep-ex/0012018 | |
| dc.identifier | http://arxiv.org/abs/hep-ex/0012018 | |
| dc.identifier | Eur.Phys.J.C19:587-651,2001 | |
| dc.identifier | doi:10.1007/s100520100627 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/207140 | |
| dc.subject | High Energy Physics - Experiment | |
| dc.title | Precise Determination of the Z Resonance Parameters at LEP : Zedometry | |
| dc.type | text |