Elsevier

Nuclear Physics B

Volume 429, Issue 3, 7 November 1994, Pages 477-502
Nuclear Physics B

Deep inelastic scattering events with a large rapidity gap at HERA

https://doi.org/10.1016/0550-3213(94)90151-1Get rights and content

Abstract

Evidence is presented using data taken with the H1 detector at HERA for a class of deep inelastic electron-proton scattering (DIS) events (5 < Q2 < 120 GeV2) at low Bjorken-x (10−4 < x < 10−2) which have almost no hadronic energy flow in a large interval of pseudo-rapidity around the proton remnant direction and which cannot be attributed to our present understanding of DIS and fluctuations in final state hadronic fragmentation. From an integrated luminosity of 273 nb−1, 734 events, that is about 5% of the total DIS sample, have no energy deposition greater than 400 MeV forward of laboratory pseudo-rapidity ηmax = 1.8 up to the largest measurable pseudo-rapidity of about 3.65. Evidence that about 10% of observed rapidity gap events are exclusive vector meson electroproduction is presented. Good descriptions of the data are obtained using models based either on a vector meson dominance like picture, which includes a large fraction of inelastic virtual photon dissociation, or on deep inelastic electron-pomeron scattering in which the partonic sub-structure of the latter is resolved.

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    2

    Supported by the Bundesministerium für Forschung und Technologie, Germany, under contract numbers 6AC17P, 6AC47P, 6DO57I, 6HH17P, 6HH27I, 6HD17I, 6HD27I, 6KI17P, 6MP17I, and6WT87P.

    3

    Supported by the UK Particle Physics and Astronomy Research Council, and formerly by the UK Science and Engineering Research Council.

    4

    Supported by FNRS-NFWO, IISN-IIKW.

    5

    Supported by the Polish State Committee for Scientific Research, grant No. 204209101.

    6

    Supported in part by USDOE grant DE F603 91ER40674.

    7

    Supported by the Swedish Natural Science Research Council.

    8

    Supported by GA ČR, grant no. 202/93/2423 and by GA AV ČR, grant no. 19095.

    9

    Supported by the Swiss National Science Foundation.

    1

    Visitor from Yerevan Phys. Inst., Armenia.

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