01 2 v 1 4 A ug 1 99 9 Measurement of D ∗ ± production and the charm contribution to F 2 in deep inelastic scattering at HERA ZEUS Collaboration

The production of D(2010) mesons in deep inelastic scattering has been measured in the ZEUS detector at HERA using an integrated luminosity of 37 pb. The decay channels D → Dπ (+ c.c.), with D → Kπ or D → Kπππ, have been used to identify the D mesons. The ep cross section for inclusive D production with 1 < Q < 600GeV and 0.02 < y < 0.7 is 8.31±0.31(stat.) −0.50(syst.) nb in the kinematic region 1.5 < pT (D ) < 15GeV and | η(D) | < 1.5. Differential cross sections are consistent with a next-to-leading-order perturbative-QCD calculation when using charmfragmentation models which take into account the interaction of the charm quark with the proton remnant. The observed cross section is extrapolated to the full kinematic region in pT (D ) and η(D) in order to determine the charm contribution, F cc̄ 2 (x,Q ), to the proton structure function. The ratio F cc̄ 2 /F2 rises from ≃10% at Q ≃ 1.8 GeV to ≃30% at Q ≃130 GeV for x values in the range 10 to 10. DESY 99-101 July 1999 The ZEUS Collaboration J. Breitweg, S. Chekanov, M. Derrick, D. Krakauer, S. Magill, B. Musgrave, A. Pellegrino, J. Repond, R. Stanek, R. Yoshida Argonne National Laboratory, Argonne, IL, USA p M.C.K. Mattingly Andrews University, Berrien Springs, MI, USA G. Abbiendi, F. Anselmo, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, G. Cara Romeo, G. Castellini, L. Cifarelli, F. Cindolo, A. Contin, N. Coppola, M. Corradi, S. De Pasquale, P. Giusti, G. Iacobucci, G. Laurenti, G. Levi, A. Margotti, T. Massam, R. Nania, F. Palmonari, A. Pesci, A. Polini, G. Sartorelli, Y. Zamora Garcia, A. Zichichi University and INFN Bologna, Bologna, Italy f C. Amelung, A. Bornheim, I. Brock, K. Coböken, J. Crittenden, R. Deffner, M. Eckert, H. Hartmann, K. Heinloth, E. Hilger, H.-P. Jakob, A. Kappes, U.F. Katz, R. Kerger, E. Paul, J. Rautenberg, H. Schnurbusch, A. Stifutkin, J. Tandler, A. Weber, H. Wieber Physikalisches Institut der Universität Bonn, Bonn, Germany c D.S. Bailey, O. Barret, W.N. Cottingham, B. Foster, G.P. Heath, H.F. Heath, J.D. McFall, D. Piccioni, J. Scott, R.J. Tapper H.H. Wills Physics Laboratory, University of Bristol, Bristol, U.K. o M. Capua, A. Mastroberardino, M. Schioppa, G. Susinno Calabria University, Physics Dept.and INFN, Cosenza, Italy f H.Y. Jeoung, J.Y. Kim, J.H. Lee, I.T. Lim, K.J. Ma, M.Y. Pac Chonnam National University, Kwangju, Korea h A. Caldwell, W. Liu, X. Liu, B. Mellado, J.A. Parsons, S. Ritz, R. Sacchi, S. Sampson, F. Sciulli Columbia University, Nevis Labs., Irvington on Hudson, N.Y., USA q J. Chwastowski, A. Eskreys, J. Figiel, K. Klimek, K. Olkiewicz, M.B. Przybycień, P. Stopa, L. Zawiejski Inst. of Nuclear Physics, Cracow, Poland j L. Adamczyk, B. Bednarek, K. Jeleń, D. Kisielewska, A.M. Kowal, T. Kowalski, M. Przybycień, E. Rulikowska-Zarȩbska, L. Suszycki, J. Zaja̧c Faculty of Physics and Nuclear Techniques, Academy of Mining and Metallurgy, Cracow, Poland j Z. Duliński, A. Kotański Jagellonian Univ., Dept. of Physics, Cracow, Poland k