Study of charm production in Z decays

R. Barate, D. Decamp, P. Ghez, C. Goy, J. P. Lees, E. Merle, M. N. Minard, B. Pietrzyk, R. Alemany, M. P. Casado, M. Chmeissani, J. M. Crespo, E. Fernandez, M. Fernandez-Bosman, L. Garrido, E. Graugès, A. Juste, M. Martinez, G. Merino, R. MiquelL. M. Mir, A. Pacheco, I. C. 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. W. Forty, M. Frank, T. C. Greening, A. W. Halley, J. B. 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. R. Tomalin, E. Tournefier, A. E. 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. C. Montret, D. Pallin, P. Perret, F. Podlyski, J. D. Hansen, J. R. Hansen, P. H. Hansen

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111 Citations (Scopus)


The production rates of D*±, D*±s, D±, D0/D̄0, D±s, and Λ+c / Λ̄-c in Z → cc̄ 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 → cc̄ events is measured to be 〈XE(D*±)〉cc̄ = 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 cc̄ pair: n̄g → cc̄ = (3.23 ± 0.48(stat.) ± 0.53(syst.))%. The ratio of the Vector/(Vector+Pseudoscalar) production rates in charmed mesons is found to be PV = 0.595 ±0.045. The fractional decay width of the Z into cc̄ pairs is determined from the sum of the production rates for various weakly decaying charmed states to be Rc = 0.1738 ± 0.0047(stat.) ± 0.0116(syst.).
Original languageEnglish
Pages (from-to)597-611
JournalEuropean Physical Journal C
Issue number4
Publication statusPublished - 1 Jan 2000

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