Measurement of the diffractive structure function FD(4)2 at HERA

This paper presents the first analysis of diffractive photon dissociation events in deep inelastic positron-proton scattering at HERA in which the proton in the final state is detected and its momentum measured. The events are selected by requiring a scattered proton in the ZEUS leading proton spect...

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Main Authors: Breitweg, J, Derrick, M, Krakauer, D, Magill, S, Mikunas, D, Musgrave, B, Repond, J, Stanek, R, Talaga, R, Yoshida, R, Zhang, H, Mattingly, M, Anselmo, F, Antonioli, P, Bari, G, Basile, M, Bellagamba, L, Boscherini, D, Bruni, A, Bruni, G, Cara Romeo, G, Castellini, G, Chiarini, M, Cifarelli, L, Cindolo, F
Format: Journal article
Language:English
Published: 1998
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author Breitweg, J
Derrick, M
Krakauer, D
Magill, S
Mikunas, D
Musgrave, B
Repond, J
Stanek, R
Talaga, R
Yoshida, R
Zhang, H
Mattingly, M
Anselmo, F
Antonioli, P
Bari, G
Basile, M
Bellagamba, L
Boscherini, D
Bruni, A
Bruni, G
Cara Romeo, G
Castellini, G
Chiarini, M
Cifarelli, L
Cindolo, F
author_facet Breitweg, J
Derrick, M
Krakauer, D
Magill, S
Mikunas, D
Musgrave, B
Repond, J
Stanek, R
Talaga, R
Yoshida, R
Zhang, H
Mattingly, M
Anselmo, F
Antonioli, P
Bari, G
Basile, M
Bellagamba, L
Boscherini, D
Bruni, A
Bruni, G
Cara Romeo, G
Castellini, G
Chiarini, M
Cifarelli, L
Cindolo, F
author_sort Breitweg, J
collection OXFORD
description This paper presents the first analysis of diffractive photon dissociation events in deep inelastic positron-proton scattering at HERA in which the proton in the final state is detected and its momentum measured. The events are selected by requiring a scattered proton in the ZEUS leading proton spectrometer (LPS) with xL > 0.97, where xL is the fraction of the incoming proton beam momentum carried by the scattered proton. The use of the LPS significantly reduces the contamination from events with diffractive dissociation of the proton into low mass states and allows a direct measurement of t, the square of the four-momentum exchanged at the proton vertex. The dependence of the cross section on t is measured in the interval 0.073 < \t\ < 0.4 GeV2 and is found to be described by an exponential shape with the slope parameter b = 7.2 ± 1.1(stat.)+0.7-0.9(syst.) GeV-2. The diffractive structure function FD(4)2 is presented as a function of xIP, ≃ 1 - xL and β, the momentum fraction of the struck quark with respect to xIP, and averaged over the t interval 0.073 < \t\ < 0.4 GeV2 and the photon virtuality range 5 < Q2 < 20 GeV2. In the kinematic range 4 x 10-4 < xIP < 0.03 and 0.015 < β < 0.5, the xIP dependence of FD(4)2 is fitted with a form (1/xIP)a , yielding a = 1.00 ± 0.09 (stat.)+0.11-0.05(syst.). Upon integration over t, the structure function FD(3)2 is determined in a kinematic range extending to higher xIP and lower β compared to our previous analysis; the results are discussed within the framework of Regge theory.
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spelling oxford-uuid:db977189-deb0-449b-9779-70b000e4e39f2022-03-27T09:11:51ZMeasurement of the diffractive structure function FD(4)2 at HERAJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:db977189-deb0-449b-9779-70b000e4e39fEnglishSymplectic Elements at Oxford1998Breitweg, JDerrick, MKrakauer, DMagill, SMikunas, DMusgrave, BRepond, JStanek, RTalaga, RYoshida, RZhang, HMattingly, MAnselmo, FAntonioli, PBari, GBasile, MBellagamba, LBoscherini, DBruni, ABruni, GCara Romeo, GCastellini, GChiarini, MCifarelli, LCindolo, FThis paper presents the first analysis of diffractive photon dissociation events in deep inelastic positron-proton scattering at HERA in which the proton in the final state is detected and its momentum measured. The events are selected by requiring a scattered proton in the ZEUS leading proton spectrometer (LPS) with xL > 0.97, where xL is the fraction of the incoming proton beam momentum carried by the scattered proton. The use of the LPS significantly reduces the contamination from events with diffractive dissociation of the proton into low mass states and allows a direct measurement of t, the square of the four-momentum exchanged at the proton vertex. The dependence of the cross section on t is measured in the interval 0.073 < \t\ < 0.4 GeV2 and is found to be described by an exponential shape with the slope parameter b = 7.2 ± 1.1(stat.)+0.7-0.9(syst.) GeV-2. The diffractive structure function FD(4)2 is presented as a function of xIP, ≃ 1 - xL and β, the momentum fraction of the struck quark with respect to xIP, and averaged over the t interval 0.073 < \t\ < 0.4 GeV2 and the photon virtuality range 5 < Q2 < 20 GeV2. In the kinematic range 4 x 10-4 < xIP < 0.03 and 0.015 < β < 0.5, the xIP dependence of FD(4)2 is fitted with a form (1/xIP)a , yielding a = 1.00 ± 0.09 (stat.)+0.11-0.05(syst.). Upon integration over t, the structure function FD(3)2 is determined in a kinematic range extending to higher xIP and lower β compared to our previous analysis; the results are discussed within the framework of Regge theory.
spellingShingle Breitweg, J
Derrick, M
Krakauer, D
Magill, S
Mikunas, D
Musgrave, B
Repond, J
Stanek, R
Talaga, R
Yoshida, R
Zhang, H
Mattingly, M
Anselmo, F
Antonioli, P
Bari, G
Basile, M
Bellagamba, L
Boscherini, D
Bruni, A
Bruni, G
Cara Romeo, G
Castellini, G
Chiarini, M
Cifarelli, L
Cindolo, F
Measurement of the diffractive structure function FD(4)2 at HERA
title Measurement of the diffractive structure function FD(4)2 at HERA
title_full Measurement of the diffractive structure function FD(4)2 at HERA
title_fullStr Measurement of the diffractive structure function FD(4)2 at HERA
title_full_unstemmed Measurement of the diffractive structure function FD(4)2 at HERA
title_short Measurement of the diffractive structure function FD(4)2 at HERA
title_sort measurement of the diffractive structure function fd 4 2 at hera
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