Eur. Phys. J. C (2009) 59: 589-606
https://doi.org/10.1140/epjc/s10052-008-0792-2

Regular Article - Experimental Physics

Study of charm fragmentation into D ^* ± mesons in deep-inelastic scattering at HERA

¹ I. Physikalisches Institut der RWTH, Aachen, Germany
² Vinca Institute of Nuclear Sciences, Belgrade, Serbia
³ School of Physics and Astronomy, University of Birmingham, Birmingham, UK
⁴ Inter-University Institute for High Energies ULB-VUB, Brussels, Belgium
⁵ Universiteit Antwerpen, Antwerpen, Belgium
⁶ National Institute for Physics and Nuclear Engineering (NIPNE), Bucharest, Romania
⁷ Rutherford Appleton Laboratory, Chilton, Didcot, UK
⁸ Institute for Nuclear Physics, Cracow, Poland
⁹ Institut für Physik, TU Dortmund, Dortmund, Germany
¹⁰ Joint Institute for Nuclear Research, Dubna, Russia
¹¹ CEA, DSM/Irfu, CE-Saclay, Gif-sur-Yvette, France
¹² DESY, Hamburg, Germany
¹³ Institut für Experimentalphysik, Universität Hamburg, Hamburg, Germany
¹⁴ Max-Planck-Institut für Kernphysik, Heidelberg, Germany
¹⁵ Physikalisches Institut, Universität Heidelberg, Heidelberg, Germany
¹⁶ Kirchhoff-Institut für Physik, Universität Heidelberg, Heidelberg, Germany
¹⁷ Institute of Experimental Physics, Slovak Academy of Sciences, Košice, Slovak Republic
¹⁸ Department of Physics, University of Lancaster, Lancaster, UK
¹⁹ Department of Physics, University of Liverpool, Liverpool, UK
²⁰ Queen Mary and Westfield College, London, UK
²¹ Physics Department, University of Lund, Lund, Sweden
²² CPPM, CNRS/IN2P3–Univ. Mediterranee, Marseille, France
²³ Departamento de Fisica Aplicada, CINVESTAV, Mérida, Yucatán, Mexico
²⁴ Departamento de Fisica, CINVESTAV, México, Mexico
²⁵ Institute for Theoretical and Experimental Physics, Moscow, Russia
²⁶ Lebedev Physical Institute, Moscow, Russia
²⁷ Max-Planck-Institut für Physik, München, Germany
²⁸ LAL, Univ Paris-Sud, CNRS/IN2P3, Orsay, France
²⁹ LLR, Ecole Polytechnique, IN2P3-CNRS, Palaiseau, France
³⁰ LPNHE, Universités Paris VI and VII, IN2P3-CNRS, Paris, France
³¹ Faculty of Science, University of Montenegro, Podgorica, Montenegro
³² Institute of Physics, Academy of Sciences of the Czech Republic, Praha, Czech Republic
³³ Faculty of Mathematics and Physics, Charles University, Praha, Czech Republic
³⁴ Dipartimento di Fisica Università di Roma Tre and INFN Roma 3, Roma, Italy
³⁵ Institute for Nuclear Research and Nuclear Energy, Sofia, Bulgaria
³⁶ Institute of Physics and Technology of the Mongolian Academy of Sciences, Ulaanbaatar, Mongolia
³⁷ Paul Scherrer Institut, Villigen, Switzerland
³⁸ Fachbereich C, Universität Wuppertal, Wuppertal, Germany
³⁹ Yerevan Physics Institute, Yerevan, Armenia
⁴⁰ DESY, Zeuthen, Germany
⁴¹ Institut für Teilchenphysik, ETH, Zürich, Switzerland
⁴² Physik-Institut der Universität Zürich, Zürich, Switzerland

^* e-mail: schoning@mail.desy.de

Received: 7 August 2008
Revised: 17 October 2008
Published online: 18 December 2008

Abstract

The process of charm quark fragmentation is studied using D ^* ± meson production in deep-inelastic scattering as measured by the H1 detector at HERA. The parameters of fragmentation functions are extracted for QCD models based on leading order matrix elements and DGLAP or CCFM evolution of partons together with string fragmentation and particle decays. Additionally, they are determined for a next-to-leading order QCD calculation in the fixed flavour number scheme using the independent fragmentation of charm quarks to D ^* ± mesons. Two different regions of phase space are investigated defined by the presence or absence of a jet containing the D ^* ± meson in the event. The fragmentation parameters extracted for the two phase space regions are found to be different.