EUROPEAN ORGANIZATION FOR NUCLEAR RESEARCH

During the years 1994–97, the emulsion target of the CHORUS detector was exposed to the wideband neutrino beam of the CERN SPS. In total about 100 000 charged-current neutrino interactions were located in the nuclear emulsion target and fully reconstructed. From this sample of events which was based on the data acquired by new automatic scanning systems, 1048 D events were selected by a pattern recognition program. They were confirmed as neutral-particle decays through visual inspection. Fragmentation properties of deep-inelastic charm production were measured using these events. Distributions of the D momentum, Feynman x (xF ), z and tan θ, the transverse angle out of the leptonic plane defined by the muon and the neutrino, are presented. The mean value of z was measured to be 〈z〉 = 0.63 ± 0.03(stat) ± 0.01(syst). From fits to the z distribution, values for the Peterson parameter P = 0.108 ± 0.017(stat) ± 0.013(syst) and the Collins–Spiller parameter CS = 0.21 +0.05 −0.04(stat) ± 0.04(syst) are found. For the average value of xF we find 〈xF 〉 = 0.38 ± 0.04(stat) ± 0.03(syst) and for the forward–backward asymmetry A = 0.79 ± 0.14(stat) ± 0.05(syst). The distribution of tan θ was measured with an average value 〈tan θ〉 = 0.030± 0.002. To be published in Physics Letters B CHORUS Collaboration G. Önengüt Çukurova University, Adana, Turkey R. van Dantzig, M. de Jong, O. Melzer, R.G. C. Oldeman1, E. Pesen, J.L. Visschers NIKHEF, Amsterdam, The Netherlands M. Güler, U. Köse, M. Serin-Zeyrek, R. Sever, P. Tolun, M.T. Zeyrek METU, Ankara, Turkey M.G. Catanesi, M. De Serio, M. Ieva, M.T. Muciaccia, E. Radicioni, S. Simone Università di Bari and INFN, Bari, Italy A. Bülte, K. Winter Humboldt Universität, Berlin, Germany2 B. Van de Vyver3,4, P. Vilain5, G. Wilquet5 Inter-University Institute for High Energies (ULB-VUB) Brussels, Belgium B. Saitta Università di Cagliari and INFN, Cagliari, Italy E. Di Capua Università di Ferrara and INFN, Ferrara, Italy S. Ogawa, H. Shibuya Toho University, Funabashi, Japan A. Artamonov6, M. Chizhov7, M. Doucet8, I.R. Hristova9, A. Kayis-Topaksu10 , T. Kawamura, D. Kolev7, H. Meinhard, J. Panman, I.M. Papadopoulos, S. Ricciardi11 , A. Rozanov12 , R. Tsenov7, J.W. E. Uiterwijk, P. Zucchelli3,13 CERN, Geneva, Switzerland J. Goldberg Technion, Haifa, Israel M. Chikawa Kinki University, Higashiosaka, Japan E. Arik Bogazici University, Istanbul, Turkey J.S. Song, C.S. Yoon Gyeongsang National University, Jinju, Korea K. Kodama, N. Ushida Aichi University of Education, Kariya, Japan S. Aoki, T. Hara Kobe University, Kobe, Japan T. Delbar, D. Favart, G. Grégoire, S. Kalinin, I. Makhlioueva Université Catholique de Louvain, Louvain-la-Neuve, Belgium P. Gorbunov, V. Khovansky, V. Shamanov, I. Tsukerman Institute for Theoretical and Experimental Physics, Moscow, Russian Federation N. Bruski, D. Frekers Westfälische Wilhelms-Universität, Münster, Germany2 K. Hoshino, J. Kawada, M. Komatsu, M. Miyanishi, M. Nakamura, T. Nakano, K. Narita, K. Niu, K. Niwa, N. Nonaka, O. Sato, T. Toshito Nagoya University, Nagoya, Japan S. Buontempo, A.G. Cocco, N. D’Ambrosio, G. De Lellis, G. De Rosa, F. Di Capua, A. Ereditato, G. Fiorillo, A. Marotta, M. Messina, P. Migliozzi, C. Pistillo, L. Scotto Lavina, P. Strolin, V. Tioukov Università Federico II and INFN, Naples, Italy K. Nakamura, T. Okusawa Osaka City University, Osaka, Japan U. Dore, P.F. Loverre, L. Ludovici, P. Righini, G. Rosa, R. Santacesaria, A. Satta, F.R. Spada Università La Sapienza and INFN, Rome, Italy E. Barbuto, C. Bozza, G. Grella, G. Romano, C. Sirignano, S. Sorrentino Università di Salerno and INFN, Salerno, Italy Y. Sato, I. Tezuka Utsunomiya University, Utsunomiya, Japan ——— 1 Now at Università La Sapienza, Rome, Italy. 2 Supported by the German Bundesministerium für Bildung und Forschung under contract numbers 05 6BU11P and 05 7MS12P. Now at SpinX Technologies, Geneva, Switzerland. Fonds voor Wetenschappelijk Onderzoek, Belgium. Fonds National de la Recherche Scientifique, Belgium. On leave of absence from ITEP, Moscow. On leave of absence and at St. Kliment Ohridski University of Sofia, Bulgaria. Now at University of Maryland, MD, USA. Now at DESY, Hamburg. On leave of absence from Çukurova University, Adana, Turkey. Now at Royal Holloway College, University of London, Egham, UK. Now at CPPM CNRS-IN2P3, Marseille, France. On leave of absence from INFN, Ferrara, Italy.