Abstract
The production of D 0, D *+, D +, \( D_s^{+} \) and \( \Lambda_c^{+} \) charm hadrons and their antiparticles in ep scattering at HERA has been studied with the ZEUS detector, using a total integrated luminosity of 372 pb−1. The fractions of charm quarks hadronising into a particular charm hadron were derived. In addition, the ratio of neutral to charged D-meson production rates, the fraction of charged D mesons produced in a vector state, and the stangeness-suppression factor have been determined. The measurements have been performed in the photoproduction regime. The charm hadrons were reconstructed in the range of transverse momentum p T > 3.8 GeV and pseudorapidity |η| < 1.6. The charm fragmentation fractions are compared to previous results from HERA and from e + e − experiments. The data support the hypothesis that fragmentation is independent of the production process.
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supported by the US Department of Energy (S. Chekanov, M. Derrick, S. Magill, B. Musgrave, J. Repond, R. Yoshida, N. Brümmer, B. Bylsma, L.S. Durkin, A. Lee, T.Y. Ling, E. Brownson, D.D. Reeder, A.A. Savin, W.H. Smith, H. Wolfe)
supported by the Italian National Institute for Nuclear Physics (INFN) (P. Antonioli, G. Bari, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, F. Cindolo, M. Corradi, A. Margotti, R. Nania, A. Polini, S. De Pasquale, S. Antonelli, M. Basile, M. Bindi, L. Cifarelli, A. Contin, G. Sartorelli, A. Zichichi, M. Capua, S. Fazio, A. Mastroberardino, M. Schioppa, G. Susinno, E. Tassi, G. Barbagli, E. Gallo, P. G. Pelfer, A. Bertolin, F. Dal Corso, S. Dusini, A. Longhin, L. Stanco, R. Brugnera, R. Carlin, A. Garfagnini, S. Limentani, G. D’Agostini, G. Marini, A. Nigro, M. Costa, M.I. Ferrero, V. Monaco, R. Sacchi, A. Solano, M. Arneodo, M. Ruspa)
supported by the German Federal Ministry for Education and Research (BMBF), under contract No. 05 H09PDF (O. Arslan, D. Bartsch, I. Brock, H. Hartmann, E. Hilger, H.-P. Jakob, M. Jüngst, S. Mergelmeyer, A.E. Nuncio-Quiroz, E. Paul, U. Samson, V. Schönberg, R. Shehzadi, M. Wlasenko)
supported by the Science and Technology Facilities Council, U.K. (J.D. Morris, P.J. Bussey, A.T. Doyle, J. Ferrando, D.H. Saxon, I.O. Skillicorn, K.R. Long, A.D. Tapper, A.M. Cooper-Sarkar, R.C.E. Devenish, B. Foster, C. Gwenlan, A. Robertson, R. Walczak, J.C. Hart, T.W. Jones, M. Wing)
supported by HIR and UMRG grants from Universiti Malaya, and an ERGS grant from the Malaysian Ministry for Higher Education (Z.A. Ibrahim, F. Mohamad Idris, W.A.T. Wan Abdullah, Z. Zolkapli)
supported by the US National Science Foundation. Any opinion, findings and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation. (Y. Ning, Z. Ren, F. Sciulli, B.Y. Oh, J.J. Whitmore)
supported by the Polish Ministry of Science and Higher Education as a scientific project No. DPN/N188/DESY/2009 (J. Chwastowski, A. Eskreys, J. Figiel, A. Galas, K. Olkiewicz, B. Pawlik, P. Stopa, L. Zawiejski)
supported by the National Science Centre under contract No. DEC-2012/06/M/ST2/00428 (L. Adamczyk, T. Bold, G. Gach, I. Grabowska-Bold, M. Guzik, D. Kisielewska, M. Przybycien, L. Suszycki)
supported by the German Federal Ministry for Education and Research (BMBF), under contract No. 05h09GUF, and the SFB 676 of the Deutsche Forschungsgemeinschaft (DFG) (R. Klanner, E. Lohrmann, P. Schleper, V. Sola, H. Stadie, J. Sztuk-Dambietz, D. Szuba, M. Turcato)
supported by the Japanese Ministry of Education, Culture, Sports, Science and Technology (MEXT) and its grants for Scientific Research (K. Nagano, K. Tokushuku, S. Yamada, Y. Yamazaki, T. Tsurugai, Y. Iga, M. Ishitsuka, T. Kanno, M. Kuze, J. Maeda, T. Nobe, R. Hori, N. Okazaki, S. Shimizu, R. Hamatsu, S. Kitamura, Y.D. Ri, )
supported by the Korean Ministry of Education and Korea Science and Engineering Foundation (D. Son)
supported by FNRS and its associated funds (IISN and FRIA) and by an Inter-University Attraction Poles Programme subsidised by the Belgian Federal Science Policy Office (K. Piotrzkowski)
supported by the Spanish Ministry of Education and Science through funds provided by CICYT (F. Barreiro, J. del Peso, C. Glasman, J. Terrón)
supported by the Natural Sciences and Engineering Research Council of Canada (NSERC) (F. Corriveau, J. Schwartz, J.F. Martin, T.P. Stewart, S. Bhadra, C.D. Catterall, G. Hartner)
partially supported by the German Federal Ministry for Education and Research (BMBF) (A. Antonov, B.A. Dolgoshein, D. Gladkov, V. Sosnovtsev, A. Stifutkin, S. Suchkov)
supported by RF Presidential grant N 3920.2012.2 for the Leading Scientific Schools and by the Russian Ministry of Education and Science through its grant for Scientific Research on High Energy Physics (R.K. Dementiev, P.F. Ermolov, L.K. Gladilin, Yu.A. Golubkov, L.A. Khein, I.A. Korzhavina, B.B. Levchenko, O.Yu. Lukina, A.S. Proskuryakov, L.M. Shcheglova, D.S. Zotkin)
supported by the Netherlands Foundation for Research on Matter (FOM) (G. Grigorescu, A. Keramidas, E. Koffeman, P. Kooijman, A. Pellegrino, H. Tiecke, M. Vázquez, L. Wiggers)
supported by the Israel Science Foundation (H. Abramowicz, O. Gueta, R. Ingbir, S. Kananov, A. Stern)
also funded by Max Planck Institute for Physics, Munich, Germany (R. Aggarwal, P. Kaur, I. Singh)
supported by the research grant No. 1 P03B 04529 (2005-2008) (A. Kotanski)
partially supported by the Polish National Science Centre projects DEC-2011/01/B/ST2/03643 and DEC-2011/03/B/ST2/00220 (W. Slominski)
now at DESY group FS-CFEL-1 (N. Coppola)
partially supported by Warsaw University, Poland (J. Tomaszewska)
supported by the Alexander von Humboldt Foundation (O. Turkot, K. Wichmann)
deceased (B.A. Dolgoshein, P.F. Ermolov, A. Eskreys)
supported by DESY, Germany (V. Aushev, Y. Aushev, V. Bokhonov, N. Zhmak)
member of National Technical University of Ukraine, Kyiv Polytechnic Institute, Kyiv, Ukraine (Y. Aushev, R. Shevchenko)
member of National Technical University of Ukraine, Kyiv, Ukraine (A. Iudin)
now at DESY ATLAS group (N. Kondrashova)
member of National University of Kyiv - Mohyla Academy, Kyiv, Ukraine (N. Kovalchuk, V. Myronenko, O. Shkola, A. Trofymov, O. Turkot, N. Zakharchuk)
Alexander von Humboldt Professor; also at DESY and University of Oxford (B. Foster)
STFC Advanced Fellow (C. Gwenlan)
also at Max Planck Institute for Physics, Munich, Germany, External Scientific Member (H. Abramowicz)
This material was based on work supported by the National Science Foundation, while working at the Foundation. (J.J. Whitmore)
member of Lódz University, Poland (W. Perlanski)
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The ZEUS collaboration., Abramowicz, H., Abt, I. et al. Measurement of charm fragmentation fractions in photoproduction at HERA. J. High Energ. Phys. 2013, 58 (2013). https://doi.org/10.1007/JHEP09(2013)058
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DOI: https://doi.org/10.1007/JHEP09(2013)058