Eur. Phys. J. C (2012) 72: 2074
https://doi.org/10.1140/epjc/s10052-012-2074-2

Regular Article - Experimental Physics

Inclusive measurement of diffractive deep-inelastic scattering 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: daum@mail.desy.de

Received: 20 March 2012
Revised: 20 April 2012
Published online: 18 July 2012

Abstract

The diffractive process ep→eXY, where Y denotes a proton or its low mass excitation with M _Y <1.6 GeV, is studied with the H1 experiment at HERA. The analysis is restricted to the phase space region of the photon virtuality 3 ≤ Q ² ≤ 1600 GeV², the square of the four-momentum transfer at the proton vertex |t|< 1.0 GeV² and the longitudinal momentum fraction of the incident proton carried by the colourless exchange x _ℙ<0.05.

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Triple differential cross sections are measured as a function of x _ℙ, Q ² and β=x/x _ℙ where x is the Bjorken scaling variable. These measurements are made after selecting diffractive events by demanding a large empty rapidity interval separating the final state hadronic systems X and Y. High statistics measurements covering the data taking periods 1999–2000 and 2004–2007 are combined with previously published results in order to provide a single set of diffractive cross sections from the H1 experiment using the large rapidity gap selection method. The combined data represent a factor between three and thirty increase in statistics with respect to the previously published results. The measurements are compared with predictions from NLO QCD calculations based on diffractive parton densities and from a dipole model. The proton vertex factorisation hypothesis is tested.