The production rates of D(*+/-) D(s)(*+/-), D(+/-), D(0)/(D) over bar(0), D(s)(+/-), and Lambda(c)(+)/<(Lambda)over bar>(-)(c) in Z --> c (c) over bar decays are measured using the LEP I data sample recorded by the ALEPH detector. The fractional energy spectrum of the D(*+/-) is well described as the sum of three contributions: charm hadronisation, b hadron decays and gluon splitting into a pair of heavy quarks. The probability for a c quark to hadronise into a D(*+) is found to be f(c --> D(*+)) = 0.233 +/- 0.010(stat.) +/- 0.011(syst.). The average fraction of the beam energy carried by D(*+/-) mesons in Z --> c (c) over bar events is measured to be (X(E)(D(*+/-)))(c (c) over bar) = 0.4878 +/- 0.0046(stat.) +/- 0.0061(syst.). The D(*+/-) energy and the hemisphere mass imbalance distributions are simultaneously used to measure the fraction of hadronic Z decays in which a gluon splits to a c (c) over bar pair: (n) over bar(g --> c (c) over bar) = (3.23 +/- 0.48(stat.) +/- 0.53(syst.))%. The ratio of the Vector/(Vector+Pseudoscalar) production rates in charmed mesons is found to be P(V) = 0.595 +/- 0.045. The fractional decay width of the Z into cc pairs is determined from the sum of the production rates for various weakly decaying charmed states to be R(c) = 0.1738 +/- 0.0047(stat.) +/- 0.0116(syst.).

Study of charm production in Z decays / R. Barate, D. Decamp, P. Ghez, C. Goy, J. Lees, E. Merle, M. Minard, B. Pietrzyk, R. Alemany, M. Casado, M. Chmeissani, J. Crespo, E. Fernandez, M. Fernandez-Bosman, L. Garrido, E. Grauges, A. Juste, M. Martinez, G. Merino, R. Miquel, L. Mir, A. Pacheco, I. Park, I. Riu, 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, U. Becker, G. Boix, M. Cattaneo, F. Cerutti, V. Ciulli, G. Dissertori, H. Drevermann, R. Forty, M. Frank, T. Greening, A. Halley, J. Hansen, J. Harvey, P. Janot, B. Jost, I. Lehraus, O. Leroy, P. Mato, A. Minten, A. Moutoussi, F. Ranjard, L. Rolandi, D. Schlatter, M. Schmitt, O. Schneider, P. Spagnolo, W. Tejessy, F. Teubert, I. Tomalin, E. Tournefier, A. Wright, Z. Ajaltouni, F. Badaud, G. Chazelle, O. Deschamps, A. Falvard, C. Ferdi, P. Gay, C. Guicheney, P. Henrard, J. Jousset, B. Michel, S. Monteil, J. Montret, D. Pallin, P. Perret, F. Podlyski, J. Hansen, J. Hansen, P. Hansen, B. Nilsson, B. Rensch, A. Waananen, G. Daskalakis, A. Kyriakis, C. Markou, E. Simopoulou, I. Siotis, A. Vayaki, A. Blondel, G. Bonneaud, J. Brient, A. Rouge, M. Rumpf, M. Swynghedauw, M. Verderi, H. Videau, E. Focardi, G. Parrini, K. Zachariadou, R. Cavanaugh, M. Corden, C. Georgiopoulos, A. Antonelli, G. Bencivenni, G. Bologna, F. Bossi, P. Campana, G. Capon, V. Chiarella, P. Laurelli, G. Mannocchi, F. Murtas, G. Murtas, L. Passalacqua, M. Pepe-Altarelli, L. Curtis, J. Lynch, P. Negus, V. O'Shea, C. Raine, P. Teixeira-Dias, A. Thompson, O. Buchmuller, S. Dhamotharan, C. Geweniger, G. Graefe, P. Hanke, G. Hansper, V. Hepp, E. Kluge, A. Putzer, J. Sommer, K. Tittel, S. Werner, M. Wunsch, R. Beuselinck, D. Binnie, W. Cameron, P. Dornan, M. Girone, S. Goodsir, E. Martin, N. Marinelli, A. Sciaba, J. Sedgbeer, E. Thomson, M. Williams, V. Ghete, P. Girtler, E. Kneringer, D. Kuhn, G. Rudolph, C. Bowdery, P. Buck, A. Finch, F. Foster, G. Hughes, R. Jones, N. Robertson, M. Williams, I. Giehl, K. Jakobs, K. Kleinknecht, G. Quast, B. Renk, E. Rohne, H. Sander, H. Wachsmuth, C. Zeitnitz, J. Aubert, C. Benchouk, A. Bonissent, J. Carr, P. Coyle, F. Etienne, F. Motsch, P. Payre, D. Rousseau, M. Talby, M. Thulasidas, M.R.A. Aleppo, M. Antonelli, F. Ragusa, V. Buscher, H. Dietl, G. Ganis, K. Huttmann, G. Lutjens, C. Mannert, W. Manner, H. Moser, S. Schael, R. Settles, H. Seywerd, H. Stenzel, W. Wiedenmann, G. Wolf, P. Azzurri, J. Boucrot, O. Callot, S. Chen, A. Cordier, M. Davier, L. Duflot, J. Grivaz, P. Heusse, A. Jacholkowska, F. Le Diberder, J. Lefrancois, A. Lutz, M. Schune, J. Veillet, I. Videau, D. Zerwas, G. Bagliesi, S. Bettarini, T. Boccali, C. Bozzi, G. Calderini, R. Dell'Orso, I. Ferrante, L. Foa, A. Giassi, A. Gregorio, F. Ligabue, A. Lusiani, P. Marrocchesi, A. Messineo, F. Palla, G. Rizzo, G. Sanguinetti, G. Sguazzoni, R. Tenchini, C. Vannini, A. Venturi, P. Verdini, G. Blair, G. Cowan, M. Green, T. Medcalf, J. Strong, J. von Wimmersperg-Toeller, D. Botterill, R. Clifft, T. Edgecock, P. Norton, J. Thompson, B. Bloch-Devaux, P. Colas, S. Emery, W. Kozanecki, E. Lancon, M. Lemaire, E. Locci, P. Perez, J. Rander, J. Renardy, A. Roussarie, J. Schuller, J. Schwindling, A. Trabelsi, B. Vallage, S. Black, J. Dann, R. Johnson, H. Kim, N. Konstantinidis, A. Litke, M. McNeil, G. Taylor, C. Booth, S. Cartwright, F. Combley, M. Kelly, H. Lehto, L. Thompson, K. Affholderbach, A. Bohrer, S. Brandt, C. Grupen, J. Hess, C. Koob, A. Misiejuk, G. Prange, U. Sieler, G. Giannini, B. Gobbo, J. Rothberg, S. Wasserbaech, S. Armstrong, P. Elmer, D. Ferguson, Y. Gao, S. Gonzalez, O. Hayes, H. Hu, S. Jin, P. McNamara, J. Nielsen, W. Orejudos, Y. Pan, Y. Saadi, I. Scott, J. Walsh, S. Wu, X. Wu, G. Zobernig. - In: THE EUROPEAN PHYSICAL JOURNAL. C, PARTICLES AND FIELDS. - ISSN 1434-6044. - 16:4(2000), pp. 597-611. [10.1007/s100520000421]

Study of charm production in Z decays

M.R.A. Aleppo;F. Ragusa;
2000

Abstract

The production rates of D(*+/-) D(s)(*+/-), D(+/-), D(0)/(D) over bar(0), D(s)(+/-), and Lambda(c)(+)/<(Lambda)over bar>(-)(c) in Z --> c (c) over bar decays are measured using the LEP I data sample recorded by the ALEPH detector. The fractional energy spectrum of the D(*+/-) is well described as the sum of three contributions: charm hadronisation, b hadron decays and gluon splitting into a pair of heavy quarks. The probability for a c quark to hadronise into a D(*+) is found to be f(c --> D(*+)) = 0.233 +/- 0.010(stat.) +/- 0.011(syst.). The average fraction of the beam energy carried by D(*+/-) mesons in Z --> c (c) over bar events is measured to be (X(E)(D(*+/-)))(c (c) over bar) = 0.4878 +/- 0.0046(stat.) +/- 0.0061(syst.). The D(*+/-) energy and the hemisphere mass imbalance distributions are simultaneously used to measure the fraction of hadronic Z decays in which a gluon splits to a c (c) over bar pair: (n) over bar(g --> c (c) over bar) = (3.23 +/- 0.48(stat.) +/- 0.53(syst.))%. The ratio of the Vector/(Vector+Pseudoscalar) production rates in charmed mesons is found to be P(V) = 0.595 +/- 0.045. The fractional decay width of the Z into cc pairs is determined from the sum of the production rates for various weakly decaying charmed states to be R(c) = 0.1738 +/- 0.0047(stat.) +/- 0.0116(syst.).
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/2434/178110
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