Eur. Phys. J. C (2010) 65: 65-79
https://doi.org/10.1140/epjc/s10052-009-1193-x

Regular Article - Experimental Physics

Measurement of charm and beauty production in deep inelastic ep scattering from decays into muons 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 Department of Physics, Panjab University, Chandigarh, India
⁸ Physics Department and INFN, Calabria University, Cosenza, Italy
⁹ Chonnam National University, Kwangju, South Korea
¹⁰ Jabatan Fizik, Universiti Malaya, 50603, Kuala Lumpur, Malaysia
¹¹ Nevis Laboratories, Columbia University, Irvington on Hudson, NY, 10027, USA
¹² The Henryk Niewodniczanski Institute of Nuclear Physics, Polish Academy of Sciences, Cracow, Poland
¹³ Faculty of Physics and Applied Computer Science, AGH-University of Science and Technology, Cracow, Poland
¹⁴ Department of Physics, Jagellonian University, Cracow, Poland
¹⁵ Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany
¹⁶ Deutsches Elektronen-Synchrotron DESY, Zeuthen, Germany
¹⁷ INFN Florence, Florence, Italy
¹⁸ University and INFN Florence, Florence, Italy
¹⁹ Fakultät für Physik der Universität Freiburg i.Br., Freiburg i.Br., Germany
²⁰ Department of Physics and Astronomy, University of Glasgow, Glasgow, UK
²¹ Department of Engineering in Management and Finance, Univ. of Aegean, Aegean, Greece
²² Institute of Exp. Physics, Hamburg University, Hamburg, Germany
²³ Imperial College London, High Energy Nuclear Physics Group, London, UK
²⁴ Institute of Particle and Nuclear Studies, KEK, Tsukuba, Japan
²⁵ Institute of Physics and Technology of Ministry of Education and Science of Kazakhstan, Almaty, Kazakhstan
²⁶ Institute for Nuclear Research, National Academy of Sciences, and Kiev National University, Kiev, Ukraine
²⁷ Center for High Energy Physics, Kyungpook National University, Daegu, South Korea
²⁸ Institut de Physique Nucléaire, Université Catholique de Louvain, Louvain-la-Neuve, Belgium
²⁹ Departamento de Física Teórica, Universidad Autónoma de Madrid, Madrid, Spain
³⁰ Department of Physics, McGill University, Montréal, Québec, Canada H3A 2T8,
³¹ Faculty of General Education, Meiji Gakuin University, Yokohama, Japan
³² Moscow Engineering Physics Institute, Moscow, Russia
³³ Institute of Nuclear Physics, Moscow State University, Moscow, Russia
³⁴ Max-Planck-Institut für Physik, Munich, Germany
³⁵ NIKHEF and University of Amsterdam, Amsterdam, Netherlands
³⁶ Physics Department, Ohio State University, Columbus, OH, 43210, USA
³⁷ Department of Physics, University of Oxford, Oxford, UK
³⁸ INFN Padova, Padova, Italy
³⁹ Dipartimento di Fisica dell’ Università and INFN, Padova, Italy
⁴⁰ Department of Physics, Pennsylvania State University, University Park, PA, 16802, USA
⁴¹ Polytechnic University, Sagamihara, Japan
⁴² Dipartimento di Fisica, Università ‘La Sapienza’ and INFN, Rome, Italy
⁴³ Rutherford Appleton Laboratory, Chilton, Didcot, Oxon, UK
⁴⁴ Raymond and Beverly Sackler Faculty of Exact Sciences, School of Physics, Tel Aviv University, Tel Aviv, Israel
⁴⁵ Department of Physics, Tokyo Institute of Technology, Tokyo, Japan
⁴⁶ Department of Physics, University of Tokyo, Tokyo, Japan
⁴⁷ Department of Physics, Tokyo Metropolitan University, Tokyo, Japan
⁴⁸ Università di Torino and INFN, Torino, Italy
⁴⁹ Università del Piemonte Orientale, Novara, and INFN, Torino, Italy
⁵⁰ Department of Physics, University of Toronto, Toronto, ON, Canada M5S 1A7,
⁵¹ Physics and Astronomy Department, University College London, London, UK
⁵² Institute of Experimental Physics, Warsaw University, Warsaw, Poland
⁵³ Institute for Nuclear Studies, Warsaw, Poland
⁵⁴ Department of Particle Physics, Weizmann Institute, Rehovot, Israel
⁵⁵ Department of Physics, University of Wisconsin, Madison, WI, 53706, USA
⁵⁶ Department of Physics, York University, Toronto, Ontario, Canada M3J 1P3,

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

Received: 24 April 2009
Revised: 2 September 2009
Published online: 11 November 2009

Abstract

The production of charm and beauty quarks in ep interactions has been measured with the ZEUS detector at HERA for squared four-momentum exchange Q ²>20 GeV², using an integrated luminosity of 126 pb⁻¹. Charm and beauty quarks were identified through their decays into muons. Differential cross sections were measured for muon transverse momenta and pseudorapidities −1.6<η ^μ <2.3, as a function of , η ^μ , Q ² and Bjorken x. The charm and beauty contributions to the proton structure function F ₂ were also extracted. The results agree with previous measurements based on independent techniques and are well described by QCD predictions.