Precise determination of the Z resonance parameters at LEP: "Zedometry"

G. Abbiendi, C. Ainsley, P. F. Åkesson, G. Alexander, J. Allison, G. Anagnostou, K. J. Anderson, S. Arcelli, S. Asai, S. F. Ashby, D. Axen, G. Azuelos, I. Bailey, A. H. Ball, E. Barberio, R. J. Barlow, T. Behnke, K. W. Bell, G. Bella, A. BelleriveG. Benelli, S. Bentvelsen, C. Beeston, S. Bethke, O. Biebel, I. J. Bloodworth, O. Boeriu, P. Bock, J. Böhme, D. Bonacorsi, M. Boutemeur, S. Braibant, P. Bright-Thomas, L. Brigliadori, R. M. Brown, H. J. Burckhart, J. Cammin, P. Capiluppi, R. K. Carnegie, B. Caron, A. A. Carter, J. R. Carter, C. Y. Chang, D. G. Charlton, P. E.L. Clarke, E. Clay, I. Cohen, J. E. Conboy, O. C. Cooke, J. Couchman, R. L. Coxe, A. Csilling, M. Cuffiani, S. Dado, G. M. Dallavalle, S. Dallison, C. Darling, A. de Roeck, E. A. de Wolf, P. Dervan, K. Desch, B. Dienes, M. S. Dixit, M. Donkers, J. Dubbert, E. Duchovni, G. Duckeck, I. P. Duerdoth, P. G. Estabrooks, E. Etzion, F. Fabbri, M. Fanti, L. Feld, P. Ferrari, F. Fiedler, I. Fleck, M. Ford, M. Foucher, A. Frey, A. Fürtjes, D. I. Futyan, P. Gagnon, J. Gascon, S. M. Gascon-Shotkin, J. W. Gary, G. Gaycken, C. Geich-Gimbel, G. Giacomelli, P. Giacomelli, R. Giacomelli, D. Glenzinski, J. Goldberg, C. Grandi, K. Graham, E. Gross, J. Grunhaus, M. Gruwé, P. O. Günther, C. Hajdu, G. G. Hanson, K. Harder, A. Harel, M. Harin-Dirac, P. A. Hart, M. Hauschild, C. M. Hawkes, R. Hawkings, R. J. Hemingway, C. Hensel, G. Herten, R. D. Heuer, M. D. Hildreth, J. C. Hill, S. J. Hillier, A. Hocker, K. Hoffman, R. J. Homer, A. K. Honma, D. Horváth, K. R. Hossain, R. Howard, P. Hüntemeyer, P. Igo-Kemenes, K. Ishii, F. R. Jacob, A. Jawahery, H. Jeremie, C. R. Jones, P. Jovanovic, T. R. Junk, N. Kanaya, J. Kanzaki, G. Karapetian, D. Karlen, V. Kartvelishvili, K. Kawagoe, T. Kawamoto, R. K. Keeler, R. G. Kellogg, B. W. Kennedy, D. H. Kim, J. Kirk, K. Klein, A. Klier, S. Kluth, T. Kobayashi, M. Kobel, T. P. Kokott, S. Komamiya, R. V. Kowalewski, T. Kress, P. Krieger, J. von Krogh, D. Krop, T. Kuhl, M. Kupper, P. Kyberd, G. D. Lafferty, R. Lahmann, W. P. Lai, H. Landsman, D. Lanske, J. Lauber, I. Lawson, J. G. Layter, A. M. Lee, A. Leins, D. Lellouch, J. Letts, L. Levinson, R. Liebisch, J. Lillich, C. Littlewood, A. W. Lloyd, S. L. Lloyd, F. K. Loebinger, G. D. Long, M. J. Losty, J. Lu, J. Ludwig, A. Macchiolo, A. Macpherson, W. Mader, M. Mannelli, S. Marcellini, T. E. Marchant, A. J. Martin, J. P. Martin, G. Martinez, T. Mashimo, P. Mättig, W. J. McDonald, J. McKenna, T. J. McMahon, R. A. McPherson, F. Meijers, P. Mendez-Lorenzo, W. Menges, S. Menke, F. S. Merritt, H. Mes, A. Michelini, S. Mihara, G. Mikenberg, D. J. Miller, W. Mohr, A. Montanari, T. Mori, U. Müller, K. Nagai, I. Nakamura, H. A. Neal, R. Nisius, S. W. O'Neale, F. G. Oakham, F. Odorici, A. Oh, A. Okpara, N. J. Oldershaw, M. J. Oreglia, S. Orito, F. Palmonari, G. Pásztor, J. R. Pater, G. N. Patrick, P. Pfeifenschneider, J. E. Pilcher, J. Pinfold, D. E. Plane, B. Poli, J. Polok, O. Pooth, M. Przybycień, A. Quadt, G. Quast, K. Rabbertz, B. Raith, C. Rembser, P. Renkel, H. Rick, N. Rodning, J. M. Roney, S. Rosati, K. Roscoe, A. M. Rossi, Y. Rozen, K. Runge, O. Runolfsson, D. R. Rust, K. Sachs, T. Saeki, O. Sahr, E. K.G. Sarkisyan, C. Sbarra, A. D. Schaile, O. Schaile, P. Scharff-Hansen, B. Schmitt, M. Schröder, M. Schumacher, C. Schwick, W. G. Scott, R. Seuster, T. G. Shears, B. C. Shen, C. H. Shepherd-Themistocleous, P. Sherwood, G. P. Siroli, A. Skuja, A. M. Smith, T. J. Smith, G. A. Snow, R. Sobie, S. Söldner-Rembold, S. Spagnolo, R. W. Springer, M. Sproston, A. Stahl, K. Stephens, K. Stoll, D. Strom, R. Ströhmer, L. Stumpf, B. Surrow, S. D. Talbot, S. Tarem, R. J. Taylor, R. Teuscher, M. Tecchio, J. Thomas, M. A. Thomson, S. Towers, D. Toya, T. Trefzger, I. Trigger, Z. Trócsányi, T. Tsukamoto, E. Tsur, M. F. Turner-Watson, I. Ueda, B. Vachon, P. Vannerem, M. Verzocchi, E. H. Vokurka, H. Voss, J. Vossebeld, A. Wagner, D. L. Wagner, D. Waller, C. P. Ward, D. R. Ward, P. M. Watkins, A. T. Watson, N. K. Watson, P. S. Wells, T. Wengler, N. Wermes, D. Wetterling, J. S. White, G. W. Wilson, J. A. Wilson, T. R. Wyatt, S. Yamashita, V. Zacek, D. Zer-Zion

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Abstract

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 LEP 1 data sample comprising 161pb-1 of integrated luminosity and 4.5 × 106 selected Z decays. An interpretation of the data in terms of contributions from pure Z exchange and from γ/Z 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, Γz = (2.4948 ± 0.0041) GeV, σ0h = (41.501 ± 0.055) nb, R = 20.823 ± 0.044, and A0,ℓFB = 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, Γinvℓℓ = 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, Nv = 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: αs(mz) = 0.127 ± 0.005 and mH = (390+750-280)GeV.

Original languageEnglish
Pages (from-to)587-651
Number of pages65
JournalEuropean Physical Journal C
Volume19
Issue number4
Publication statusPublished - Jan 1 2001
Externally publishedYes

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All Science Journal Classification (ASJC) codes

  • Engineering (miscellaneous)
  • Physics and Astronomy (miscellaneous)

Cite this

Abbiendi, G., Ainsley, C., Åkesson, P. F., Alexander, G., Allison, J., Anagnostou, G., ... Zer-Zion, D. (2001). Precise determination of the Z resonance parameters at LEP: "Zedometry". European Physical Journal C, 19(4), 587-651.