https://doi.org/10.1007/s100529801046
Diffractive dijet production at HERA
12
I. Physikalisches Institut der RWTH, Aachen, Germany
35
III. Physikalisches Institut der RWTH, Aachen, Germany
32
School of Physics and Space Research, University of Birmingham, Birmingham, UK
13
Inter-University Institute for High Energies ULB-VUB, Brussels, Belgium
14
Universitaire Instelling Antwerpen, Wilrijk, Belgium
22
Rutherford Appleton Laboratory, Chilton, Didcot, UK
38
Institute for Nuclear Physics, Cracow, Poland
31
Physics Department and IIRPA, University of California, California, Davis, USA
24
Institut für Physik, Universität Dortmund, Dortmund, Germany
25
DSM/DAPNIA, CEA/Saclay, Gif-sur-Yvette, France
5
DESY, Hamburg, Germany
17
II. Institut für Experimentalphysik, Universität Hamburg, Hamburg, Germany
9
Max-Planck-Institut für Kernphysik, Heidelberg, Germany
16
Physikalisches Institut, Universität Heidelberg, Heidelberg, Germany
11
Institut für Hochenergiephysik, Universität Heidelberg, Heidelberg, Germany
27
Institut für experimentelle und angewandte Physik, Universität Kiel, Kiel, Germany
8
Slovak Academy of Sciences, Institute of Experimental Physics, Košice, Slovak Republic
19
School of Physics and Chemistry, University of Lancaster, Lancaster, UK
23
Department of Physics, University of Liverpool, Liverpool, UK
30
Queen Mary and Westfield College, London, UK
29
Physics Department, University of Lund, Lund, Swedeng
2
Department of Physics and Astronomy, University of Manchester, Manchester, UK
21
CPPM, Université d’Aix-Marseille II, IN2P3-CNRS, Marseille, France
7
Institute for Theoretical and Experimental Physics, Moscow, Russia
3
Lebedev Physical Institute, Moscow, Russia
20
Max-Planck-Institut für Physik, München, Germany
15
LAL, Université de Paris-Sud, IN2P3-CNRS, Orsay, France
4
LPNHE, Ecole Polytechnique, IN2P3-CNRS, Palaiseau, France
6
LPNHE, Universités Paris VI and VII, IN2P3-CNRS, Paris, France
26
Academy of Sciences of the Czech Republic, Institute of Physics, Praha, Czech Republic
36
Nuclear Center, Charles University, Praha, Czech Republic
18
INFN Roma 1 and Dipartimento di Fisica, Università Roma 3, Roma, Italy
37
Paul Scherrer Institut, Villigen, Switzerland
40
Fachbereich Physik, Bergische Universität Gesamthochschule Wuppertal, Wuppertal, Germany
1
Institut für Hochenergiephysik, DESY, Zeuthen, Germany
34
Institut für Teilchenphysik, ETH, Zürich, Switzerland
33
Physik-Institut der Universität Zürich, Zürich, Switzerland
39
Institut für Physik, Humboldt-Universität, Berlin, Germany
28
Rechenzentrum, Bergische Universität Gesamthochschule Wuppertal, Wuppertal, Germany
10
Visitor from Yerevan Physics Institute, Armenia
Received:
18
August
1998
Accepted:
14
December
1998
Published online: 17 September 2013
Interactions of the type ep → eXY are studied, where the component X of the hadronic final state contains two jets and is well separated in rapidity from a leading baryonic system Y. Analyses are performed of both resolved and direct photoproduction and of deep-inelastic scattering with photon virtualities in the range 7.5 < Q
2 < 80 GeV2. Cross sections are presented where Y has mass M
Y
< 1.6 GeV, the squared four-momentum transferred at the proton vertex satisfies |t| < 1 GeV2 and the two jets each have transverse momentum p
T
jet
> 5 GeV relative to the photon direction in the rest frame of X. Models based on a factorisable diffractive exchange with a gluon dominated structure, evolved to a scale set by the transverse momentum 
of the outgoing partons from the hard interaction, give good descriptions of the data. Exclusive 
production, as calculated in perturbative QCD using the squared proton gluon density, represents at most a small fraction of the measured cross section. The compatibility of the data with a breaking of diffractive factorisation due to spectator interactions in resolved photoproduction is investigated.
© Springer-Verlag, 1999
