1. Measurement of $$\Gamma (Z^0 \to b\bar b)/\Gamma (Z^0 \to hadrons)$$ using impact parameters and leptons
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R. Lahmann, D. C. Imrie, J. C. Clayton, B. C. Shen, G. P. Siroli, J. King, A. K. Honma, Christoph Schwick, W. G. Scott, Gideon Bella, H. J. Burckhart, M. Jones, Jacqueline Batley, G. A. Snow, C. P. Ward, M. J. Pearce, Horst Breuker, Margret Fincke-Keeler, D. L. Rees, M. J. Losty, Otmar Biebel, P. Igo-Kemenes, C. Jui, J. Hart, C. Sbarra, S. Barnett, Claude Leroy, A. Astbury, J. P. Pansart, J. D. Gillies, P. Pfister, R. Bartoldus, H. Jeremie, U. Müller, James Pinfold, G. E. Richards, D. Pitman, A. J. Martin, F. C. Grant, M. H. Lehto, D. G. Charlton, D. L. Wagner, R. J. Barlow, R. E. Hughes-Jones, U. Maur, D. Hochman, D. G. Fong, H. O. Ogren, Michael Dittmar, G. Yekutieli, D. J. Miller, Christoph Geich-Gimbel, G. Beaudoin, C. K. Hargrove, N. I. Geddes, Matthias Schröder, H. Lafoux, N. Paz-Jaoshvili, J. Steuerer, J. Gascon, H. von der Schmitt, T. G. Shears, B. Boden, K. Stephens, J. R. McNutt, R.J. Akers, J. Lauber, E. do Couto e Silva, A. Buijs, D. M. Strom, C. Stegmann, H. Takeda, D. M. Gingrich, D. E. Plane, P. Bentkowski, A. A. Carter, Roger Jones, R. Van Kooten, M. G. Rison, T. J. McMahon, B. Poli, F. G. Oakham, G. M. Dallavalle, M. Hansroul, Madjid Boutemeur, E. Lefebvre, J. W. Gary, Marcello Mannelli, J. E. Duboscq, H. Deng, R. Humbert, Shlomo Dado, Tohru Takeshita, J. Schwiening, R. K. Carnegie, F. X. Gentit, B. Fabbro, O. Schaile, P. Berlich, J. A. Wilson, F. Odorici, J. E. Conboy, B. Panzer-Steindel, R. Kowalewski, R. Yaari, D. J.P. Dumas, R. J. Hemingway, Georges Azuelos, P. G. Estabrooks, R. K. Keeler, P. M. Watkins, V. Gibson, S. Bethke, P. Scharff-Hansen, G. Quast, J. M. Lorah, W. Schappert, P. Kroll, Marco Cuffiani, John Baines, X. C. Lou, Silvia Arcelli, W. R. Gibson, A. M. Rossi, C. H. Shepherd-Themistocleous, P. Jovanovic, T. Tsukamoto, W. Mohr, J. F. Kral, Austin Ball, H. M. Fischer, M. A. Whallev, K. W. Bell, Max Weber, D. Menszner, Randall Sobie, G. D. Lafferty, S. L. Chu, A. Beck, J. C. Hill, A. Michelini, H. Mes, Norbert Wermes, J. von Krogh, I. P. Duerdoth, A. C. Janissen, J. M. Roney, E. Heflin, Sherry Towers, P. S. Wells, Misao Sasaki, R. J. Homer, M. Hauschild, Alessandro Montanari, R. M. Brown, T. Kawamoto, A. M. Smith, P. M. Hattersley, J. Banks, Lorne Levinson, G. Vasseur, Dave Robinson, Gideon Alexander, P. A. Elcombe, Giora Mikenberg, C. Markus, P. Paschievici, Terry Richard Wyatt, B. Lorazo, D. R. Ward, L. A. del Pozo, C. Y. Chang, M. F. Turner, B. W. Kennedy, T. W. Pritchard, E. Torrente-Lujan, G. Transtromer, Paolo Capiluppi, Kiyotomo Kawagoe, John Hobbs, C. Moisan, R. D. Heuer, M. Coupland, Andris Skuja, G. A. Beck, Fabrizio Fabbri, Achim Stahl, S. Orito, M. Rosvick, J. Becker, P. Teixeira-Dias, D. Van den plas, P. Weber, F. S. Merritt, F. Scharf, Tetsuro Mashimo, G. J. VanDalen, R. Mir, Gregor Herten, D. R. Rust, C. Wahl, B. Schmitt, B. Wilkens, A. Skillman, A. M. Lee, J. E. Pilcher, W. Gorn, A. Gaidot, T. Wlodek, M. Sproston, G. Giacomelli, J. A. McKenna, M. J. Oreglia, N. Tesch, A. Dieckmann, A. D. Schaile, V. H. Winterer, P. Schenk, J. R. Carter, P. F. Harrison, G. N. Patrick, Stephen Lloyd, M. Tecchio, M. S. Dixit, Ehud Duchovni, M. Jimack, H. Ihssen, Frans Meijers, S. W. Gensler, S. J. Hillier, T. Kobayashi, P. E.L. Clarke, H. Przysiezniak, M. Fierro, M. Yurko, S. A. Robins, J. P. Martin, P. W. Jeffreys, S. De Jong, P. Bright-Thomas, S. W. O'Neale, M. A. Thomson, K. J. Anderson, J. G. Layter, T. Hilse, O. Runolfsson, P. Poffenberger, C. Beeston, Claudio Grandi, D. A. Hinshaw, T. Behnke, D. Axen, A. Jawahery, Peter Sherwood, I. J. Bloodworth, R. W. Springer, Alexander Wagner, J. Hagemann, J. Ludwig, K. Runge, P. Bock, G. Duckeck, R. Ströhmer, G. T. Zorn, H. M. Bosch, Wolfram Dietrich Zeuner, A. Yeaman, M. Settles, M. Foucher, N. K. Watson, G. W. Wilson, D. Karlen, C. Burgard, C. M. Hawkes, M. Cooper, Erez Etzion, Daniel Lellouch, Takehiko Mori, Stefan Kluth, Shlomit Tarem, S. Rossberg, C. J. Oram, R. P. Middleton, J. Goldberg, B. Nellen, P. Leblanc, M. Morii, T. J. Smith, Peter R Hobson, H. G. Evans, M. J. Goodrick, I. Cohen, P. Routenburg, Gunter Wolf, P. Mättig, Sachio Komamiya, N. J. Tesilian, E. Ros, A. T. Watson, S. Wotton, T. P. Kokott, A. Luig, Paul Kyberd, F. K. Loebinger, A. Rollnik, R. Giacomelli, J. Mildenberger, Harold Nguyen, Gordon H. Hanson, M. W. Redmond, John Allison, R. G. Kellogg, D. S. Koetke, Stefano Marcellini, and James Letts
- Subjects
Physics ,Particle physics ,Physics and Astronomy (miscellaneous) ,Astrophysics::High Energy Astrophysical Phenomena ,Electron–positron annihilation ,High Energy Physics::Phenomenology ,Hadron ,Elementary particle ,Bottom quark ,Charm quark ,Nuclear physics ,High Energy Physics::Experiment ,Production (computer science) ,Impact parameter ,Engineering (miscellaneous) ,Particle Physics - Experiment ,Bar (unit) - Abstract
A measurement of\(\Gamma _{b\bar b} /\Gamma _{had} \equiv \Gamma (Z^0 \to b\bar b)/\Gamma (Z^0 \to hadrons)\) is presented using a “mixed tag” method involving the identification of\(Z^0 \to b\bar b\) events by two different techniques. The first uses the large impact parameter of tracks emerging from the decay ofb-flavoured hadrons and the second their semi-leptonic decay. The identification efficiencies are measured from the data using all possible combinations of the two tags in opposite hemispheres. The method is therefore insensitive to Monte Carlo modelling of bottom quark production and ofb-flavoured hadron production and decay properties, and depends only weakly on the simulation of the detector. The data sample collected by OPAL at LEP in 1990 and 1991 is considered. The result is: $$\frac{{\Gamma _{b\bar b} }}{{\Gamma _{had} }} = 0.218 \pm 0.006(stat) \pm 0.007(syst) \pm 0.007(\Gamma _{c\bar c} /\Gamma _{had} ),$$ where the systematic uncertainty due to the charm quark partial width has been separated from the other systematic uncertainties. Combination with previous OPAL measurements gives: $$\frac{{\Gamma _{b\bar b} }}{{\Gamma _{had} }} = 0.220 \pm 0.004(stat) \pm 0.006(syst) \pm 0.006(\Gamma _{c\bar c} /\Gamma _{had} ),$$
- Published
- 1994
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