© 2005, Springer New York LLC. All rights reserved. The production of D∗+, D0, D+, D+s and Λ+c charm hadrons and their antiparticles in ep scattering at HERA was measured with the ZEUS detector using an integrated luminosity of 79 pb−1. The measurement has been performed in the photoproduction regime with the exchanged-photon virtuality Q2 < 1GeV2 and for photon-proton centre-of-mass energies in the range 130 3.8GeV and pseudorapidity |η(D,Λc)| < 1.6. The production cross sections were used to determine the ratio of neutral and charged D-meson production rates, Ru/d, the strangeness-suppression factor, γs, and the fraction of charged D mesons produced in a vector state, Pdv. The measured Ru/d and γs values agree with those obtained in deep inelastic scattering and in e+e- annihilations. The measured Pdv value is smaller than, but consistent with, the previous measurements. The fractions of c quarks hadronising as a particular charm hadron, f(c → D, Λc), were derived in the given kinematic range. The measured open-charm fragmentation fractions are consistent with previous results, although the measured f(c → D*+) is smaller and f(c → Λ+c) is larger than those obtained in e+e- annihilations. These results generally support the hypothesis that fragmentation proceeds independently of the hard sub-process.
European Physical Journal C
Chekanov, S.; Derrick, M.; Magill, S.; Miglioranzi, S.; Musgrave, B.; Repond, J.; Yoshida, R.; Mattingly, Margarita C. K.; Pavel, N.; Yagües Molina, A. G.; Antonioli, P.; Bari, G.; Basile, M.; Bellagamba, L.; Boscherini, D.; Bruni, A.; Bruni, G.; Cara Romeo, G.; Cifarelli, L.; Cindolo, F.; Contin, A.; Corradi, M.; De Pasquale, S.; Giusti, P.; Iacobucci, G.; Margotti, A.; Montanari, A.; Nania, R.; Palmonari, F.; Pesci, A.; and Polini, A., "Measurement of Charm Fragmentation Ratios and Fractions in Photoproduction at HERA" (2005). Faculty Publications. 2070.
Open access article retrieved March 18, 2021 from 10.1140/epjc/s2005-02397-3