The properties of the Z resonance are measured from the analysis of 4.5 million Z decays into fermion pairs collected with the ALEPII detector at LEP. The data are consistent with lepton universality. The resonance parameters are measured to be M(Z) = (91.1885 +/- 0.0031) GeV/c(2), Gamma(Z) = (2.4941 +/- 0.0043) GeV, sigma(had)(0) = (41.559 +/- 0.058) nb and, combining the three lepton flavours, R(l) = 20.725 +/- 0.039. The corresponding number of light neutrino species is N(v) = 2.983 +/- 0.013 and the strong coupling constant is alpha(s)(M(Z)) = 0.114 +/- 0.004 +/- 0.002(QCD) + 0.005 log(10) [M(H)/150 GeV/c(2)]. The lepton pair forward-backward asymmetry is measured to be A(FB)(0,l) = 0.0173 +/- 0.0016 from which the effective weak mixing angle is described: sin(2) theta(eff)(lept) = 0.23089 +/- 0.00089. The measurement of the leptonic width Gamma(ll) = 84.02 +/- 0.15 MeV leads to a determination of the effective rho parameter rho(eff)(lept) = 1.0064 +/- 0.0018. The data support the Standard Model and favour a light Higgs.

Measurement of the Z resonance parameters at LEP / Barate, R., Focardi, E., Ghez, P., Goy, C., Lees, J.P., Lucotte, A., Merle, E., Minard, M.N., Pietrzyk, B., Alemany, R., Casado, M.P., Chmeissani, M., Comas, P., Crespo, J.M., Fernandez, E., Fernandez Bosman, M., Garrido, L., Grauges, E., Juste, A., Martinez, M., et al.. - In: THE EUROPEAN PHYSICAL JOURNAL. C, PARTICLES AND FIELDS. - ISSN 1434-6044. - STAMPA. - 14:(2000), pp. 1-50. [10.1007/s100520050732]

Measurement of the Z resonance parameters at LEP

FOCARDI, ETTORE;CIULLI, VITALIANO;
2000

Abstract

The properties of the Z resonance are measured from the analysis of 4.5 million Z decays into fermion pairs collected with the ALEPII detector at LEP. The data are consistent with lepton universality. The resonance parameters are measured to be M(Z) = (91.1885 +/- 0.0031) GeV/c(2), Gamma(Z) = (2.4941 +/- 0.0043) GeV, sigma(had)(0) = (41.559 +/- 0.058) nb and, combining the three lepton flavours, R(l) = 20.725 +/- 0.039. The corresponding number of light neutrino species is N(v) = 2.983 +/- 0.013 and the strong coupling constant is alpha(s)(M(Z)) = 0.114 +/- 0.004 +/- 0.002(QCD) + 0.005 log(10) [M(H)/150 GeV/c(2)]. The lepton pair forward-backward asymmetry is measured to be A(FB)(0,l) = 0.0173 +/- 0.0016 from which the effective weak mixing angle is described: sin(2) theta(eff)(lept) = 0.23089 +/- 0.00089. The measurement of the leptonic width Gamma(ll) = 84.02 +/- 0.15 MeV leads to a determination of the effective rho parameter rho(eff)(lept) = 1.0064 +/- 0.0018. The data support the Standard Model and favour a light Higgs.
2000
14
1
50
Barate, R.; Focardi, Ettore; Ghez, P.; Goy, C.; Lees, J. P.; Lucotte, A.; Merle, E.; Minard, M. N.; Pietrzyk, B.; Alemany, R.; Casado, M. P.; Chmeissa...espandi
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Utilizza questo identificatore per citare o creare un link a questa risorsa: https://hdl.handle.net/2158/780732
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