Abstract
Diffractive dissociation of quasi-real photons at a photon-proton centre of mass energy of W ≈ 200 GeV is studied with the ZEUS detector at HERA. The process under consideration is γp → XN, where X is the diffractively dissociated photon system of mass MX and N is either a proton or a nucleonic system with mass MN < 2 GeV. The cross section for this process in the interval 3 < MX < 24 GeV relative to the total photoproduction cross section was measured to be σD partial/σtot = 6.2 ± 0.2(stat) ± 1.4(syst)%. After extrapolating this result to the mass interval of mφ 2 < MX 2 < 0.05W2 and correcting it for proton dissociation, the fraction of the total cross section attributed to single diffractive photon dissociation, γp → Xp, is found to be σSD/σtot = 13.3 ± 0.5(stat) ± 3.6(syst)%. The mass spectrum of the dissociated photon system in the interval 8 < MX < 24 GeV can be described by the triple pomeron (IP IP IP) diagram with an effective pomeron intercept of αIP(0) = 1.12 ± 0.04(stat) ± 0.08(syst). The cross section for photon dissociation in the range 3 < MX < 8 GeV is significantly higher than that expected from the triple pomeron amplitude describing the region 8 < MX < 24 GeV. Assuming that this discrepancy is due to a pomeron-pomeron-reggeon (IP IP IR) term, its contribution to the diffractive cross section in the interval 3 < MX < 24 GeV is estimated to be fIP IP IR = 26 ± 3(stat) ± 12(syst)%.
Original language | English |
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Pages (from-to) | 421-435 |
Number of pages | 15 |
Journal | Zeitschrift fur Physik C-Particles and Fields |
Volume | 75 |
Issue number | 3 |
DOIs | |
Publication status | Published - 1997 Jul |
Bibliographical note
Funding Information:h supported by the Korean Ministry of Education and Korea Science and Engineering Foundation i supported by the Netherlands Foundation for Research on Matter (FOM) j supported by the Polish State Committee for Scientific Research, grant No. 115/E-343/SPUB/P03/120/96 k supported by the Polish State Committee for Scientific Research (grant No. 2 P03B 083 08) and Foundation for Polish-German Collaboration l partially supported by the German Federal Ministry for Education and Science, Research and Technology (BMBF) m supported by the German Federal Ministry for Education and Science, Research and Technology (BMBF), and the Fund of Fundamental Research of Russian Ministry of Science and Education and by INTAS-Grant No.
Funding Information:
93-63 n supported by the Spanish Ministry of Education and Science through funds provided by CICYT o supported by the Particle Physics and Astronomy Research Council p supported by the US Department of Energy q supported by the US National Science Foundation
Funding Information:
supported by the Natural Sciences and Engineering Research Council of Canada (NSERC) b supported by the FCAR of Québec, Canada c supported by the German Federal Ministry for Education and Science, Research and Technology (BMBF), under contract numbers 057BN19P, 057FR19P, 057HH19P, 057HH29P, 057SI75I d supported by the MINERVA Gesellschaft für Forschung GmbH, the German Israeli Foundation, and the U.S.-Israel Binational Science Foundation e supported by the German Israeli Foundation, and by the Israel Science Foundation f supported by the Italian National Institute for Nuclear Physics (INFN) g supported by the Japanese Ministry of Education, Science and Culture (the Monbusho) and its grants for Scientific Research
Funding Information:
1 also at IROE Florence, Italy 2 now at Univ. of Salerno and INFN Napoli, Italy 3 now at Univ. of Crete, Greece 4 supported by Worldlab, Lausanne, Switzerland 5 now OPAL 6 retired 7 also at University of Torino and Alexander von Humboldt Fellow 8 now at Dongshin University, Naju, Korea 9 also at DESY and Alexander von Humboldt Fellow 10 Alfred P. Sloan Foundation Fellow 11 supported by an EC fellowship number ERBFMBICT 950172 12 now at SAP A.G., Walldorf 13 visitor from Florida State University 14 now at ALCATEL Mobile Communication GmbH, Stuttgart 15 now at DESY Computer Center 16 supported by European Community Program PRAXIS XXI 17 now at DESY-Group FDET 18 visitor from Kyungpook National University, Taegu, Korea, partially supported by DESY 19 now at Fermi National Accelerator Laboratory (FNAL), Batavia, IL, USA 20 now at Siemens A.G., Munich 21 now at NORCOM Infosystems, Hamburg 22 now at Oxford University, supported by DAAD fellowship HSP II-AUFE III 23 now at ATLAS Collaboration, Univ. of Munich 24 now at Clinical Operational Research Unit, University College, London 25 on leave from MSU, supported by the GIF, contract I-0444-176.07/95 26 now a self-employed consultant 27 supported by an EC fellowship 28 PPARC Post-doctoral Fellow 29 now at Conduit Communications Ltd., London, U.K. 30 now at CERN 31 supported by JSPS Postdoctoral Fellowships for Research Abroad 32 now at Department of Energy, Washington 33 now at Lawrence Berkeley Laboratory, Berkeley 34 now at Yale University, New Haven, CT 35 supported by a MINERVA Fellowship 36 partially supported by DESY 37 present address: Tokyo Metropolitan College of Allied Medical Sciences, Tokyo 116, Japan 38 supported by the Polish State Committee for Scientific Research, grant No. 2P03B09308 39 supported by the Polish State Committee for Scientific Research, grant No. 2P03B09208
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)