Measurement of the forward-backward asymmetry in Z → bb̄ and Z → cc̄ decays with leptons: The ALEPH collaboration

A. Heister, S. Schael, R. Barate, I. De Bonis, D. Decamp, C. Goy, J. P. Lees, E. Merle, M. N. Minard, B. Pietrzyk, G. Boix, S. Bravo, M. P. Casado, M. Chmeissani, J. M. Crespo, E. Fernandez, M. Fernandez-Bosman, Ll Garrido, E. Graugés, M. MartinezG. Merino, R. Miquel, Ll 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, O. Buchmüller, M. Cattaneo, F. Cerutti, B. Clerbaux, H. Drevermann, R. W. Forty, M. Frank, F. Gianotti, T. C. Greening, J. B. Hansen, J. Harvey, D. E. Hutchcroft, P. Janot, B. Jost, M. Kado, P. Mato, A. Moutoussi, F. Ranjard, L. Rolandi, D. Schlatter, O. Schneider, G. Sguazzoni, W. Tejessy, F. Teubert, A. Valassi, I. Videau, J. Ward, F. Badaud, A. Falvard, P. Gay, P. Henrard, J. Jousset, B. Michel, S. Monteil, J. C. Montret, D. Pallin, P. Perret, J. D. Hansen, J. R. Hansen, P. H. Hansen, B. S. Nilsson, A. Wäänänen, A. Kyriakis, C. Markou, E. Simopoulou, A. Vayaki, K. Zachariadou, A. Blondel, G. Bonneaud, J. C. Brient, A. Rougé, 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, H. Stenzel, 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. Thomson, 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, K. Jakobs, K. Kleinknecht, G. Quast, B. Renk, H. G. Sander, H. Wachsmuth, C. Zeitnitz, A. Bonissent, J. Carr, P. Coyle, O. Leroy, P. Payre, D. Rousseau, M. Talby, F. Ragusa, H. Dietl, G. Ganis, K. Hüttmann, G. Lütjens, C. Mannert, W. Männer, H. G. Moser, R. Settles, W. Wiedenmann, G. Wolf, J. Boucrot, O. Callot, M. Davier, L. Duflot, J. F. Grivaz, Ph Heusse, A. Jacholkowska, J. Lefrançois, J. J. Veillet, C. Yuan, G. Bagliesi, T. Boccali, L. Fòa, A. Giammanco, A. Giassi, F. Ligabue, A. Messineo, F. Palla, G. Sanguinetti, A. Sciab`a, 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, B. Bloch-Devaux, P. Colas, S. Emery, W. Kozanecki, E. Lan¸con, 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, A. Böohrer, S. Brandt, C. Grupen, A. Ngac, G. Prange, U. Sieler, G. Giannini, J. Rothberg, S. R. Armstrong, K. Berkelman, K. Cranmer, D. P.S. Ferguson, Y. Gao, S. González, O. J. Hayes, H. Hu, S. Jin, J. Kile, P. A. McNamara, J. Nielsen, Y. B. Pan, J. H. von Wimmersperg-Toeller, W. Wiedenmann, J. Wu, S. L. Wu, X. Wu, G. Zobernig, G. Dissertori

    Research output: Contribution to journalArticle

    Abstract

    The sample of hadronic Z decays collected by the ALEPH detector at LEP in the years 1991-1995 is analysed in order to measure the forward-backward asymmetry in Z → bb̄ and Z → cc̄ events and the B 0 -B̄ 0 average mixing parameter χ̄. Quark charges are tagged by the charges of electrons and muons produced in b and e semileptonic decays. Multivariate analyses are used to separate the event flavours and b → ℓ/b → c → ℓ processes. The b and c quark asymmetries are measured simultaneously; the average mixing parameter and the pole asymmetries are determined to be χ̄ = 0.1196 ± 0.0049 (stat.) -0.0050 +0.0043 (syst.), A FB 0,b = 0.0998 ± 0.0040 (stat.) ± 0.0017 (syst.), A FB 0,c = 0.0732 ± 0.0053 (stat.) ± 0.0037 (syst.). These asymmetries, combined with the ALEPH measurements of the b asymmetry using inclusive b hadron decays and of the c asymmetry using reconstructed D mesons, correspond to a value of the effective electroweak mixing angle of sin 2 θ W eff = 0.23188 ± 0.00046.

    Original languageEnglish (US)
    Pages (from-to)177-191
    Number of pages15
    JournalEuropean Physical Journal C
    Volume24
    Issue number2
    DOIs
    StatePublished - Jun 2002

    ASJC Scopus subject areas

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

    Fingerprint Dive into the research topics of 'Measurement of the forward-backward asymmetry in Z → bb̄ and Z → cc̄ decays with leptons: The ALEPH collaboration'. Together they form a unique fingerprint.

  • Cite this

    Heister, A., Schael, S., Barate, R., De Bonis, I., Decamp, D., Goy, C., Lees, J. P., Merle, E., Minard, M. N., Pietrzyk, B., Boix, G., Bravo, S., Casado, M. P., Chmeissani, M., Crespo, J. M., Fernandez, E., Fernandez-Bosman, M., Garrido, L., Graugés, E., ... Dissertori, G. (2002). Measurement of the forward-backward asymmetry in Z → bb̄ and Z → cc̄ decays with leptons: The ALEPH collaboration. European Physical Journal C, 24(2), 177-191. https://doi.org/10.1007/s100520200950