The forward-backward asymmetry for charm quarks at the Z

• Published in: Physics letters. B Vol. 434; no. 3; pp. 415 - 425
• Main Authors: Boix, G., Casado, M.P., Garrido, Ll, Graugès, E., Merino, G., Mir, Ll.M., Sanchez, F., Creanza, D., de Palma, M., Nuzzo, S., Raso, G., Ruggieri, F., Wang, T., Xue, S., Cattaneo, M., Halley, A.W., Hansen, J.B., Mato, P., Minten, A., Pacheco, A., Rousseau, D., Schlatter, D., Schneider, O., Tomalin, I.R., Chazelle, G., Henrard, P., Monteil, S., Pallin, D., Podlyski, F., Rosnet, P., Wäänänen, A., Siotis, I., Valassi, A., Focardi, E., Parrini, G., Zachariadou, K., Bencivenni, G., Murtas, G.P., Curtis, L., Lynch, J.G., Teixeira-Dias, P., Dhamotharan, S., Hanke, P., Tittel, K., Goodsir, S., Kuhn, D., Betteridge, A.P., Finch, A.J., Jakobs, K., Kleinknecht, K., Renk, B., Sander, H.-G., van Gemmeren, P., Zeitnitz, C., Aubert, J.J., Bonissent, A., Carr, J., Motsch, F., Aleppo, M., Büscher, V., Cowan, G., Ganis, G., Moser, H.-G., Schael, S., Schune, M.-H., Azzurri, P., Bagliesi, G., Bettarini, S., Bozzi, C., Calderini, G., Dell'Orso, R., Fantechi, R., Forti, F., Giorgi, M.A., Sguazzoni, G., Verdini, P.G., Clifft, R.W., Thompson, J.C., Emery, S., Lemaire, M.-C., Schuller, J.-P., Trabelsi, A., Vallage, B., Johnson, R.P., McNeil, M.A., Booth, C.N., Cartwright, S., Kelly, M.S., Lehto, M., Brandt, S., Grupen, C., Rothberg, J., Elmer, P., González, S., Hayes, O.J., Nachtman, J.M., Saadi, Y., Walsh, J., Wu, Sau Lan, Wu, X.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 27.08.1998; Elsevier
• Subjects: High Energy Physics - Experiment; Physics
• ISSN: 0370-2693; 1873-2445
• DOI: 10.1016/S0370-2693(98)00818-1

The data set collected with the ALEPH detector from 1991 to 1995 at LEP has been analysed to measure the charm forward-backward asymmetry at the Z. Out of a total of 4.1 million hadronic Z decays, about 36000 high momentum D ∗+ , D + and D 0 decays were reconstructed, of which 80% originate from Z→c c ̄ events. The forward-backward asymmetry was measured at three energy points: A FB c ( s =89.37 GeV)= −1.0±4.4 % A FB c ( s =91.22 GeV)= 6.3±1.0 % A FB c ( s =92.96 GeV)= 11.0±3.4 % . From this analysis, a value of the effective electroweak mixing angle sin 2 θ e ff W =0.2321±0.0016 is extracted.