Precise values of the Z resonance cross sections and lepton pair forward-backward asymmetries are measured from a sample of 1.3 million Z decays into hadrons and charged leptons taken with the ALEPH detector at LEP. A silicon-tungsten luminosity calorimeter was installed in ALEPH in 1992, permitting the determination of the absolute luminosity to a systematic precision of 0.15% (experimental) and 0.25% (theoretical). This is combined with a better understanding of the hadronic event selection and an improved tau pair selection. Including the ALEPH results of the past three years one obtains sigma(h)0 = (41.60 +/- 0.16) nb, and R(l) = 20.69 +/- 0.09. The corresponding number of light neutrino species is N(v) = 2.983 +/- 0.034. The lepton pair forward-backward' asymmetry is used to derive the ratio of vector to axial-vector couplings of leptons: g(V)2(M(Z)2)/g(A)2(M(Z)2) = 0.0058 +/- 0.0011. An application of these results to constrain one model with extra Z bosons is presented.

Z-production cross-sections and lepton pair forward-backward asymmetries / D. Buskulic, D. Casper, I. Debonis, D. Decamp, P. Ghez, C. Goy, J. Lees, M. Minard, P. Odier, B. Pietrzyk, F. Ariztizabal, P. Comas, J. Crespo, I. Efthymiopoulos, E. Fernandez, M. Fernandezbosman, V. Gaitan, L. Garrido, M. Martinez, T. Mattison, S. Orteu, A. Pacheco, C. Padilla, A. Pascual, D. Creanza, M. Depalma, A. Farilla, G. Iaselli, G. Maggi, N. Marinelli, S. Natali, S. Nuzzo, A. Ranieri, G. Raso, F. Romano, F. Ruggieri, G. Selvaggi, L. Silvestris, P. Tempesta, G. Zito, Y. Chai, D. Huang, X. Huang, J. Lin, T. Wang, Y. Xie, D. Xu, R. Xu, J. Zhang, L. Zhang, W. Zhao, E. Blucher, G. Bonvicini, J. Boudreau, H. Drevermann, R. Forty, G. Ganis, C. Gay, M. Girone, R. Hagelberg, J. Harvey, J. Hilgart, R. Jacobsen, B. Jost, J. Knobloch, I. Lehraus, M. Maggi, C. Markou, P. Mato, H. Meinhard, A. Minten, R. Miquel, K. Moffeit, P. Palazzi, J. Pater, J. Perlas, P. Perrodo, J. Pusztaszeri, F. Ranjard, L. Rolandi, J. Rothberg, T. Ruan, M. Saich, D. Schlatter, M. Schmelling, F. Sefkow, W. Tejessy, I. Tomalin, R. Veenhof, H. Wachsmuth, S. Wasserbaech, W. Wiedenmann, T. Wildish, W. Witzeling, J. Wotschack, Z. Ajaltouni, M. Bardadinotwinowska, A. Barres, C. Boyer, A. Falvard, P. Gay, C. Guicheney, P. Henrard, J. Jousset, B. Michel, J. Montret, D. Pallin, P. Perret, F. Podlyski, J. Proriol, F. Saadi, T. Fearnley, J. Hansen, J. Hansen, J. Hansen, P. Hansen, S. Johnson, R. Mollerud, B. Nilsson, A. Kyriakis, E. Simopoulou, I. Siotis, A. Vayaki, K. Zachariadou, J. Badier, A. Blondel, G. Bonneaud, J. Brient, P. Bourdon, G. Fouque, L. Passalacqua, A. Rouge, M. Rumpf, R. Tanaka, M. Verderi, H. Videau, D. Candlin, M. Parsons, E. Veitch, E. Focardi, L. Moneta, G. Parrini, M. Corden, M. Delfino, G. Georgiopoulos, D. Jaffe, D. Levinthal, A. Antonelli, G. Bencivenni, G. Bologna, F. Bossi, P. Campana, G. Capon, F. Cerutti, V. Chiarella, G. Felici, P. Laurelli, G. Mannocchi, G. Murtas, M. Pepealtarelli, S. Salomone, P. Colrain, I. Tenhave, I. Knowles, J. Lynch, W. Maitland, W. Morton, C. Raine, P. Reeves, J. Scarr, K. Smith, M. Smith, A. Thompson, S. Thorn, R. Turnbull, U. Becker, O. Braun, C. Geweniger, P. Hanke, V. Hepp, E. Kluge, A. Putzer, B. Rensch, M. Schmidt, H. Stenzel, K. Tittel, M. Wunsch, R. Beuselinck, D. Binnie, W. Cameron, M. Cattaneo, D. Colling, P. Dornan, J. Hassard, N. Konstantinidis, A. Moutoussi, J. Nash, D. Payne, G. Sanmartin, J. Sedgbeer, A. Wright, P. Girtler, D. Kuhn, G. Rudolph, R. Vogl, C. Bowdery, T. Brodbeck, A. Finch, F. Foster, G. Hughes, D. Jackson, N. Keemer, M. Nuttall, A. Patel, T. Sloan, S. Snow, E. Whelan, A. Galla, A. Greene, K. Kleinknecht, J. Raab, B. Renk, H. Sander, H. Schmidt, S. Walther, R. Wanke, B. Wolf, A. Bencheikh, C. Benchouk, A. Bonissent, D. Calvet, J. Carr, P. Couyle, C. Diaconu, F. Etienne, D. Nicod, P. Payre, L. Roos, D. Rousseau, P. Schwemling, M. Talby, S. Adlung, R. Assmann, C. Bauer, W. Blum, D. Brown, P. Cattaneo, B. Dehning, H. Dietl, F. Dydak, M. Frank, A. Halley, K. Jakobs, J. Lauber, G. Lutjens, G. Lutz, W. Manner, H. Moser, R. Richter, J. Schroder, A. Schwarz, R. Settles, H. Seywerd, U. Stierlin, U. Stiegler, R. Stdenis, G. Wolf, R. Alemany, J. Boucrot, O. Callot, A. Cordier, M. Davier, L. Duflot, J. Grivaz, Heussep, P. Janot, D. Kim, F. Lediberder, J. Lefrancois, A. Lutz, G. Musolino, M. Schune, J. Veillet, I. Videau, D. Abbaneo, G. Bagliesi, G. Batignani, U. Bottigli, C. Bozzi, G. Calderini, M. Carpinelli, M. Ciocci, V. Ciulli, R. Dellorso, I. Ferrante, F. Fidecaro, L. Foa, F. Forti, A. Giassi, M. Giorgi, A. Gregorio, F. Ligabue, A. Lusiani, P. Marrocchesi, E. Martin, A. Messineo, F. Palla, G. Rizzo, G. Sanguinetti, P. Spagnolo, J. Steinberger, R. Tenchini, G. Tonelli, G. Triggiani, A. Valassi, C. Vannini, A. Venturi, P. Verdini, J. Walsh, A. Betteridge, Y. Gao, M. Green, D. Johnson, P. March, T. Medcalf, L. Mir, I. Quazi, J. Strong, V. Bertin, D. Botterill, R. Clifft, T. Edgecock, S. Haywood, M. Edwards, P. Norton, J. Thompson, B. Blochdevaux, P. Colas, H. Duarte, S. Emery, W. Kozanecki, E. Lancon, M. Lemaire, E. Locci, B. Marx, P. Perez, J. Rander, J. Renardy, A. Rosowsky, A. Roussarie, J. Schuller, J. Schwindling, D. Mohand, B. Vallage, R. Johnson, A. Litke, G. Taylor, J. Wear, W. Babbage, E. Beddall, C. Booth, S. Cartwright, F. Combley, I. Dawson, C. Rankin, L. Thompson, A. Bohrer, S. Brandt, G. Cowan, E. Feigl, C. Grupen, G. Lutters, J. Minguetrodriguez, F. Rivera, P. Saraiva, U. Schafer, L. Smolik, R. Dellamarina, G. Giannini, B. Gobbo, L. Pitis, F. Ragusa, L. Bellantoni, W. Chen, J. Conway, Z. Feng, D. Ferguson, Y. Gao, J. Grahl, J. Harton, O. Hayes, H. Hu, J. Nachtman, Y. Pan, Y. Saadi, M. Schmitt, I. Scott, V. Sharma, J. Turk, A. Walsh, F. Weber, S. Wu, X. Wu, M. Zheng, J. Yamartino, G. Zobernig. - In: ZEITSCHRIFT FÜR PHYSIK. C, PARTICLES AND FIELDS. - ISSN 0170-9739. - 62:4(1994), pp. 539-550.

Z-production cross-sections and lepton pair forward-backward asymmetries

F. Ragusa;
1994

Abstract

Precise values of the Z resonance cross sections and lepton pair forward-backward asymmetries are measured from a sample of 1.3 million Z decays into hadrons and charged leptons taken with the ALEPH detector at LEP. A silicon-tungsten luminosity calorimeter was installed in ALEPH in 1992, permitting the determination of the absolute luminosity to a systematic precision of 0.15% (experimental) and 0.25% (theoretical). This is combined with a better understanding of the hadronic event selection and an improved tau pair selection. Including the ALEPH results of the past three years one obtains sigma(h)0 = (41.60 +/- 0.16) nb, and R(l) = 20.69 +/- 0.09. The corresponding number of light neutrino species is N(v) = 2.983 +/- 0.034. The lepton pair forward-backward' asymmetry is used to derive the ratio of vector to axial-vector couplings of leptons: g(V)2(M(Z)2)/g(A)2(M(Z)2) = 0.0058 +/- 0.0011. An application of these results to constrain one model with extra Z bosons is presented.
Settore FIS/01 - Fisica Sperimentale
Settore FIS/04 - Fisica Nucleare e Subnucleare
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/176635
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