Based on a sample of four million events collected by ALEPH from 1991 to 1995, a measurement of the forward-backward asymmetry in Z -> b-barb decays using inclusive final states is presented. High-performance tagging of b-barb events in a wide angular range is achieved using neural network techniques. An optimal hemisphere charge estimator is built by merging primary and secondary vertex information, leading kaon identification and jet charge in a neural network. The average charge asymmetry, the flavour tagging efficiencies and mean b-hemisphere charges are measured from data and used to extract the pole b asymmetry in the Standard Model A^{0,b}_{FB} = 0.1009 +- 0.0027 (stat) +- 0.0015 (syst), corresponding to a value of the effective weak mixing angle of sin^2(theta_W^{eff}) = 0.23193 +- 0.00056.
Measurement of A**b(FB) using inclusive b hadron decays / A. Heister, S. Schael, R. Barate, I. De Bonis, D. Decamp, C. Goy, J.P. Lees, E. Merle, M.N. Minard, B. Pietrzyk, S. Bravo, M.P. Casado, M. Chmeissani, J.M. Crespo, E. Fernandez, M. Fernandez-Bosman, L. Garrido, E. Grauges, M. Martinez, G. Merino, R. Miquel, L.M. Mir, A. Pacheco, H. Ruiz, A. Colaleo, D. Creanza, M. De Palma, G. Iaselli, G. Maggi, M. Maggi, S. Nuzzo, A. Ranieri, G. Raso, F. Ruggieri, G. Selvaggi, L. Silvestris, P. Tempesta, A. Tricomi, G. Zito, X. Huang, J. Lin, Q. Ouyang, T. Wang, Y. Xie, R. Xu, S. Xue, J. Zhang, L. Zhang, W. Zhao, D. Abbaneo, P. Azzurri, G. Boix, O. Buchmuller, M. Cattaneo, F. Cerutti, B. Clerbaux, G. Dissertori, H. Drevermann, R.W. Forty, M. Frank, T.C. Greening, J.B. Hansen, John Harvey, P. Janot, B. Jost, M. Kado, P. Mato, A. Moutoussi, F. Ranjard, Gigi Rolandi, D. Schlatter, O. Schneider, W. Tejessy, F. Teubert, E. Tournefier, J. Ward, Z. Ajaltouni, F. Badaud, A. Falvard, P. Gay, P. Henrard, J. Jousset, B. Michel, S. Monteil, J.C. Montret, D. Pallin, P. Perret, F. Podlyski, J.D. Hansen, J.R. Hansen, P.H. Hansen, B.S. Nilsson, A. Waananen, A. Kyriakis, C. Markou, E. Simopoulou, A. Vayaki, K. Zachariadou, A. Blondel, G. Bonneaud, J.C. Brient, A. Rouge, M. Rumpf, M. Swynghedauw, M. Verderi, H. Videau, V. Ciulli, E. Focardi, G. Parrini, A. Antonelli, M. Antonelli, G. Bencivenni, G. Bologna, F. Bossi, P. Campana, G. Capon, V. Chiarella, P. Laurelli, G. Mannocchi, F. Murtas, G.P. Murtas, L. Passalacqua, M. Pepe-Altarelli, P. Spagnolo, A.W. Halley, J.G. Lynch, P. Negus, V. O'Shea, C. Raine, A.S. Thompson, S. Wasserbaech, R. Cavanaugh, S. Dhamotharan, C. Geweniger, P. Hanke, G. Hansper, V. Hepp, E.E. Kluge, A. Putzer, J. Sommer, K. Tittel, S. Werner, M. Wunsch, R. Beuselinck, D.M. Binnie, W. Cameron, P.J. Dornan, M. Girone, N. Marinelli, J.K. Sedgbeer, J.C. Thompson, V.M. Ghete, P. Girtler, E. Kneringer, D. Kuhn, G. Rudolph, E. Bouhova-Thacker, C.K. Bowdery, A.J. Finch, F. Foster, G. Hughes, R.W.L. Jones, M.R. Pearson, N.A. Robertson, I. Giehl, K. Jakobs, K. Kleinknecht, G. Quast, B. Renk, E. Rohne, H.G. Sander, H. Wachsmuth, C. Zeitnitz, A. Bonissent, J. Carr, P. Coyle, O. Leroy, P. Payre, D. Rousseau, M. Talby, M. Aleppo, F. Ragusa, A. David, H. Dietl, G. Ganis, K. Huttmann, G. Lutjens, C. Mannert, W. Manner, H.G. Moser, R. Settles, H. Stenzel, W. Wiedenmann, G. Wolf, J. Boucrot, O. Callot, M. Davier, L. Duflot, J.F. Grivaz, P. Heusse, A. Jacholkowska, J. Lefrancois, J.J. Veillet, I. Videau, C. Yuan, Giuseppe Bagliesi, T. Boccali, G. Calderini, L. Foa, A. Giammanco, A. Giassi, F. Ligabue, A. Messineo, F. Palla, G. Sanguinetti, A. Sciaba, G. Sguazzoni, R. Tenchini, A. Venturi, P.G. Verdini, G.A. Blair, G. Cowan, M.G. Green, T. Medcalf, A. Misiejuk, J.A. Strong, P. Teixeira-Dias, J.H. Von Wimmersperg-Toeller, R.W. Clifft, T.R. Edgecock, P.R. Norton, I.R. Tomalin, Brigitte Bloch-Devaux, P. Colas, S. Emery, W. Kozanecki, E. Lancon, M.C. Lemaire, E. Locci, P. Perez, J. Rander, J.F. Renardy, A. Roussarie, J.P. Schuller, J. Schwindling, A. Trabelsi, B. Vallage, N. Konstantinidis, A.M. Litke, G. Taylor, C.N. Booth, S. Cartwright, F. Combley, M. Lehto, L.F. Thompson, K. Affholderbach, Armin Boehrer, S. Brandt, C. Grupen, A. Ngac, G. Prange, U. Sieler, G. Giannini, J. Rothberg, S.R. Armstrong, K. Cranmer, P. Elmer, D.P.S. Ferguson, Y. Gao, S. Gonzalez, O.J. Hayes, H. Hu, S. Jin, J. Kile, P.A. McNamara,, III, J. Nielsen, W. Orejudos, Y.B. Pan, Y. Saadi, I.J. Scott, J. Walsh, Sau Lan Wu, X. Wu, G. Zobernig. - In: THE EUROPEAN PHYSICAL JOURNAL. C, PARTICLES AND FIELDS. - ISSN 1434-6044. - 22:2(2001), pp. 201-215. [10.1007/s100520100812]
Measurement of A**b(FB) using inclusive b hadron decays
M. Aleppo;F. Ragusa;
2001
Abstract
Based on a sample of four million events collected by ALEPH from 1991 to 1995, a measurement of the forward-backward asymmetry in Z -> b-barb decays using inclusive final states is presented. High-performance tagging of b-barb events in a wide angular range is achieved using neural network techniques. An optimal hemisphere charge estimator is built by merging primary and secondary vertex information, leading kaon identification and jet charge in a neural network. The average charge asymmetry, the flavour tagging efficiencies and mean b-hemisphere charges are measured from data and used to extract the pole b asymmetry in the Standard Model A^{0,b}_{FB} = 0.1009 +- 0.0027 (stat) +- 0.0015 (syst), corresponding to a value of the effective weak mixing angle of sin^2(theta_W^{eff}) = 0.23193 +- 0.00056.
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