# Diffractive Deep-Inelastic Scattering with a Leading Proton at HERA

Abstract : The cross section for the diffractive deep-inelastic scattering process $ep \to e X p$ is measured, with the leading final state proton detected in the H1 Forward Proton Spectrometer. The data analysed cover the range \xpom <0.1 in fractional proton longitudinal momentum loss, 0.08 < |t| < 0.5 GeV^{-2} in squared four-momentum transfer at the proton vertex, 2 < Q^2 < 50 GeV^2 in photon virtuality and 0.004 < \beta = x / \xpom < 1, where x is the Bjorken scaling variable. For $\xpom \lapprox 10^{-2}$, the differential cross section has a dependence of approximately ${\rm d} \sigma / {\rm d} t \propto e^{6 t}$, independently of \xpom, \beta and Q^2 within uncertainties. The cross section is also measured triple differentially in \xpom, \beta and Q^2. The \xpom dependence is interpreted in terms of an effective pomeron trajectory with intercept $\alpha_{\pom}(0)=1.114 \pm 0.018 ({\rm stat.}) \pm 0.012 ({\rm syst.}) ^{+0.040}_{-0.020} ({\rm model})$ and a sub-leading exchange. The data are in good agreement with an H1 measurement for which the event selection is based on a large gap in the rapidity distribution of the final state hadrons, after accounting for proton dissociation contributions in the latter. Within uncertainties, the dependence of the cross section on x and Q^2 can thus be factorised from the dependences on all studied variables which characterise the proton vertex, for both the pomeron and the sub-leading exchange.
Document type :
Journal articles

http://hal.in2p3.fr/in2p3-00079761
Contributor : Sabine Starita <>
Submitted on : Monday, January 8, 2007 - 10:30:46 AM
Last modification on : Wednesday, September 16, 2020 - 4:24:43 PM

### Citation

A. Aktas, V. Andreev, T. Anthonis, S. Aplin, A. Asmone, et al.. Diffractive Deep-Inelastic Scattering with a Leading Proton at HERA. European Physical Journal C: Particles and Fields, Springer Verlag (Germany), 2006, 48, pp.749-766. ⟨10.1140/epjc/s10052-006-0046-0⟩. ⟨in2p3-00079761⟩

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