Eur. Phys. J. C (2009) 60: 25-45
https://doi.org/10.1140/epjc/s10052-009-0881-x

Regular Article - Experimental Physics

Production of excited charm and charm-strange mesons at HERA

¹ Argonne National Laboratory, Argonne, IL, 60439-4815, USA
² Andrews University, Berrien Springs, MI, 49104-0380, USA
³ INFN Bologna, Bologna, Italy
⁴ University and INFN Bologna, Bologna, Italy
⁵ Physikalisches Institut der Universität Bonn, Bonn, Germany
⁶ H.H. Wills Physics Laboratory, University of Bristol, Bristol, UK
⁷ Calabria University, Physics Department and INFN, Cosenza, Italy
⁸ Chonnam National University, Kwangju, South Korea
⁹ Jabatan Fizik, Universiti Malaya, 50603, Kuala Lumpur, Malaysia
¹⁰ Nevis Laboratories, Columbia University, Irvington on Hudson, NY, 10027, USA
¹¹ The Henryk Niewodniczanski Institute of Nuclear Physics, Polish Academy of Sciences, Cracow, Poland
¹² Faculty of Physics and Applied Computer Science, AGH-University of Science and Technology, Cracow, Poland
¹³ Department of Physics, Jagellonian University, Cracow, Poland
¹⁴ Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany
¹⁵ Deutsches Elektronen-Synchrotron DESY, Zeuthen, Germany
¹⁶ INFN Florence, Florence, Italy
¹⁷ University and INFN Florence, Florence, Italy
¹⁸ Fakultät für Physik der Universität Freiburg i.Br., Freiburg i.Br., Germany
¹⁹ Department of Physics and Astronomy, University of Glasgow, Glasgow, UK
²⁰ Department of Engineering in Management and Finance, Univ. of Aegean, Mytilene, Greece
²¹ Hamburg University, Institute of Exp. Physics, Hamburg, Germany
²² Imperial College London, High Energy Nuclear Physics Group, London, UK
²³ Institute of Particle and Nuclear Studies, KEK, Tsukuba, Japan
²⁴ Institute of Physics and Technology of Ministry of Education and Science of Kazakhstan, Almaty, Kazakhstan
²⁵ Institute for Nuclear Research, National Academy of Sciences, Kiev and Kiev National University, Kiev, Ukraine
²⁶ Kyungpook National University, Center for High Energy Physics, Daegu, South Korea
²⁷ Institut de Physique Nucléaire, Université Catholique de Louvain, Louvain-la-Neuve, Belgium
²⁸ Departamento de Física Teórica, Universidad Autónoma de Madrid, Madrid, Spain
²⁹ Department of Physics, McGill University, Montréal, Québec, Canada H3A 2T8,
³⁰ Meiji Gakuin University, Faculty of General Education, Yokohama, Japan
³¹ Moscow Engineering Physics Institute, Moscow, Russia
³² Moscow State University, Institute of Nuclear Physics, Moscow, Russia
³³ Max-Planck-Institut für Physik, München, Germany
³⁴ NIKHEF and University of Amsterdam, Amsterdam, Netherlands
³⁵ Physics Department, Ohio State University, Columbus, OH, 43210, USA
³⁶ Department of Physics, University of Oxford, Oxford, UK
³⁷ INFN Padova, Padova, Italy
³⁸ Dipartimento di Fisica dell’ Università and INFN, Padova, Italy
³⁹ Department of Physics, Pennsylvania State University, University Park, PA, 16802, USA
⁴⁰ Polytechnic University, Sagamihara, Japan
⁴¹ Dipartimento di Fisica, Università ‘La Sapienza’ and INFN, Rome, Italy
⁴² Rutherford Appleton Laboratory, Chilton, Didcot, Oxon, UK
⁴³ Raymond and Beverly Sackler Faculty of Exact Sciences, School of Physics, Tel Aviv University, Tel Aviv, Israel
⁴⁴ Department of Physics, Tokyo Institute of Technology, Tokyo, Japan
⁴⁵ Department of Physics, University of Tokyo, Tokyo, Japan
⁴⁶ Tokyo Metropolitan University, Department of Physics, Tokyo, Japan
⁴⁷ Università di Torino and INFN, Torino, Italy
⁴⁸ Università del Piemonte Orientale, Novara, and INFN, Torino, Italy
⁴⁹ Department of Physics, University of Toronto, Toronto, Ontario, Canada M5S 1A7,
⁵⁰ Physics and Astronomy Department, University College London, London, UK
⁵¹ Warsaw University, Institute of Experimental Physics, Warsaw, Poland
⁵² Institute for Nuclear Studies, Warsaw, Poland
⁵³ Department of Particle Physics, Weizmann Institute, Rehovot, Israel
⁵⁴ Department of Physics, University of Wisconsin, Madison, WI, 53706, USA
⁵⁵ Department of Physics, York University, Toronto, Ontario, Canada M3J 1P3,

^* e-mail: tobias.haas@desy.de

Received: 24 November 2008
Published online: 4 February 2009

Abstract

The production of excited charm, D ₁(2420)⁰ and D ₂ ^* (2460)⁰, and charm-strange, D _s1(2536)^±, mesons in ep collisions was measured with the ZEUS detector at HERA using an integrated luminosity of 126 pb⁻¹. Masses, widths and helicity parameters were determined. The measured yields were converted to the rates of c quarks hadronising as a given excited charm meson and to the ratios of the dominant D ₂ ^* (2460)⁰ and D _s1(2536)^± branching fractions. A search for the radially excited charm meson, D ^*′(2640)^±, was also performed. The results are compared with those measured previously and with theoretical expectations.