Eur. Phys. J. C (1998) 1: 97-107
https://doi.org/10.1007/BF01245800

Measurement of the inclusive di-jet cross section in photoproduction and determination of an effective parton distribution in the photon

¹³ I. Physikalisches Institut der RWTH, D-52074, Aachen, Germany
³⁵ III. Physikalisches Institut der RWTH, D-52074, Aachen, Germany
³⁰ School of Physics and Space Research, University of Birmingham, B15 2TT, Birmingham, UK
¹⁴ Inter-University Institute for High Energies ULB-VUB, Brussels, Belgium
¹⁵ Universitaire Instelling Antwerpen, B-2610, Wilrijk, Belgium
²² Rutherford Appleton Laboratory, 0QX, Chilton, Didcot, UK
³⁷ Institute for Nuclear Physics, PL-30055, Cracow, Poland
²⁹ Physics Department and IIRPA, University of California, Davis, California, USA
¹⁷ Institut für Physik, Universität Dortmund, Dortmund, Germany
³³ DSM/DAPNIA, CEA/Saclay, F-91191, Gif-sur-Yvette, France
⁴² Department of Physics and Astronomy, University of Glasgow, G12 8QQ, Glasgow, UK
⁷ DESY, Hamburg, Germany
⁴¹ I. Institut für Experimentalphysik, Universität Hamburg, D-22761, Hamburg, Germany
² II. Institut für Experimentalphysik, Universität Hamburg, D-22761, Hamburg, Germany
¹¹ Max-Planck-Institut für Kernphysik, D-69029, Heidelberg, Germany
¹⁹ Physikaliches Institut, Universität Heidelberg, D-69120, Heidelberg, Germany
¹² Institut für Hochenergiephysik, Universität Heidelberg, D-69120, Heidelberg, Germany
²⁶ Institut für Reine und Angewandte Kernphysik, Universität Kiel, D-24118, Kiel, Germany
¹⁰ Institut of Experimental Physics, Slovak Academy of Sciences, 04353 Koice, Slovak Republic
²⁰ School of Physics and Chemistry, University of Lancaster, LA1 4YB, Lancaster, UK
²³ Department of Physics, University of Liverpool, L69 3BX, Liverpool, UK
²⁴ Queen Mary and Westfield College, E1 4NS, London, UK
³⁹ Physics Department, University of Lund, cS-22362, Lund, Sweden
³ Physics Department, University of Manchester, M13 9PL, Manchester, UK
²¹ CPPM, Université Aix-Marseille II, IN2P3-CNRS, F-13288, Marseille, France
⁹ Institute for Theoretical and Experimental Physics, RU-117924, Moscow, Russia
⁴ Lebedev Physical Institute, RU-117924, Moscow, Russia
¹⁸ Max-Planck Institut für Physik, D-80805, München, Germany
¹⁶ LAL, Université de Paris-Sud, IN2P3-CNRS, F-91405, Orsay, France
⁵ LPNHE, Ecole Polytechnique, IN2P3-CNRS, F-91128, Palaiseau, France
⁸ LPNHE, Université Paris VI and VII, IN2P3-CNRS, F-75252, Paris, France
²⁵ Institute of Physics, Czech Academy of Sciences of the Czech Republic, Praha, CZ-18040, Czech Republic
³⁶ Nuclear Center, Charles University, CZ-18000, Praha, Czech Republic
³⁴ INFN Roma 1 and Dipartimento di Fisica, Università Roma 3, I-00146, Roma, Italy
³⁸ Paul Scherrer Institut, CH-5232, Villigen, Switzerland
¹ Fachbereich Physik, Bergische Universität Gesamthochschule Wuppertal, D-42097, Wuppertal, Germany
⁶ DESY, Institut für Hochenergiephysik, D-15738, Zeuthen, Germany
³² Institut für Teilchenphysik, ETH, CH-8093, Zürich, Switzerland
³¹ Physik-Institut der Universität Zürich, CH-8001, Zürich, Switzerland
⁴⁰ Institut für Physik, Humboldt-Universität, D-10115, Berlin, Germany
²⁷ Rechenzentrum, Bergische Universität Gesamthochshule Wuppertal, D-42097, Wuppertal, Germany
²⁸ Visitor from Physics Dept., University Louisville, USA

Received: 5 September 1997
Published online: 27 February 2005

Abstract

The double-differential inclusive di-jet cross section in photoproduction processes is measured with the H1 detector at HERA. The cross section is determined as a function of the average transverse jet energyE _T ^jets for ranges of the fractional energyξ _γ ^jets of the parton from the photon side. An effective leading order parton distribution in the photon is determined at large parton fractional energies for scale between 80 <p _T ² < 1250 GeV². The measurement is compatible with the logarithmic scale dependence that is predicted by perturbative QCD.