https://doi.org/10.1140/epjc/s10052-012-2047-5
Regular Article - Experimental Physics
Measurement of beauty and charm photoproduction using semi-muonic decays in dijet events at HERA
1
I. Physikalisches Institut der RWTH, Aachen, Germany
2
Vinca Institute of Nuclear Sciences, University of Belgrade, 1100, Belgrade, Serbia
3
School of Physics and Astronomy, University of Birmingham, Birmingham, UK
4
Inter-University Institute for High Energies ULB-VUB, Brussels and Universiteit Antwerpen, Antwerpen, Belgium
5
National Institute for Physics and Nuclear Engineering (NIPNE), Bucharest, Romania
6
STFC, Rutherford Appleton Laboratory, Didcot, Oxfordshire, UK
7
Institute for Nuclear Physics, Cracow, Poland
8
Institut für Physik, TU Dortmund, Dortmund, Germany
9
Joint Institute for Nuclear Research, Dubna, Russia
10
CEA, DSM/Irfu, CE-Saclay, Gif-sur-Yvette, France
11
DESY, Hamburg, Germany
12
Institut für Experimentalphysik, Universität Hamburg, Hamburg, Germany
13
Max-Planck-Institut für Kernphysik, Heidelberg, Germany
14
Physikalisches Institut, Universität Heidelberg, Heidelberg, Germany
15
Kirchhoff-Institut für Physik, Universität Heidelberg, Heidelberg, Germany
16
Institute of Experimental Physics, Slovak Academy of Sciences, Košice, Slovak Republic
17
Department of Physics, University of Lancaster, Lancaster, UK
18
Department of Physics, University of Liverpool, Liverpool, UK
19
School of Physics and Astronomy, Queen Mary, University of London, London, UK
20
Physics Department, University of Lund, Lund, Sweden
21
CPPM, Aix-Marseille Univ, CNRS/IN2P3, 13288, Marseille, France
22
Departamento de Fisica Aplicada, CINVESTAV, Mérida, Yucatán, México
23
Departamento de Fisica, CINVESTAV IPN, México City, México
24
Institute for Theoretical and Experimental Physics, Moscow, Russia
25
Lebedev Physical Institute, Moscow, Russia
26
Max-Planck-Institut für Physik, München, Germany
27
LAL, Université Paris-Sud, CNRS/IN2P3, Orsay, France
28
LLR, Ecole Polytechnique, CNRS/IN2P3, Palaiseau, France
29
LPNHE, Université Pierre et Marie Curie Paris 6, Université Denis Diderot Paris 7, CNRS/IN2P3, Paris, France
30
Faculty of Science, University of Montenegro, Podgorica, Montenegro
31
Institute of Physics, Academy of Sciences of the Czech Republic, Praha, Czech Republic
32
Faculty of Mathematics and Physics, Charles University, Praha, Czech Republic
33
Dipartimento di Fisica, Università di Roma Tre and INFN Roma 3, Roma, Italy
34
Institute for Nuclear Research and Nuclear Energy, Sofia, Bulgaria
35
Institute of Physics and Technology of the Mongolian Academy of Sciences, Ulaanbaatar, Mongolia
36
Paul Scherrer Institut, Villigen, Switzerland
37
Fachbereich C, Universität Wuppertal, Wuppertal, Germany
38
Yerevan Physics Institute, Yerevan, Armenia
39
DESY, Zeuthen, Germany
40
Institut für Teilchenphysik, ETH, Zürich, Switzerland
41
Physik-Institut der Universität Zürich, Zürich, Switzerland
* e-mail: kruegerk@mail.desy.de
Received:
11
May
2012
Revised:
30
May
2012
Published online:
13
July
2012
Measurements of cross sections for beauty and charm events with dijets and a muon in the photoproduction regime at HERA are presented. The data were collected with the H1 detector and correspond to an integrated luminosity of 179 pb−1. Events with dijets of transverse momentum 
and 
in the pseudorapidity range −1.5<η
jet<2.5 in the laboratory frame are selected in the kinematic region of photon virtuality Q
2<2.5 GeV2 and inelasticity 0.2<y<0.8. One of the two selected jets must be associated to a muon with 
in the pseudorapidity range −1.3<η
μ
<1.5. The fractions of beauty and charm events are determined using the impact parameters of the muon tracks with respect to the primary vertex and their transverse momentum relative to the axis of the associated jet. Both variables are reconstructed using the H1 vertex detector. The measurements are in agreement with QCD predictions at leading and next-to-leading order.
© Springer-Verlag / Società Italiana di Fisica, 2012
