/ Experiment-HEP hep-ex/0606003

Diffractive deep-inelastic scattering with a leading proton at HERA

Aktas, A. ; Andreev, V. ; Anthonis, T. ; Antunovic, B. ; Aplin, S. ; Asmone, A. ; Astvatsatourov, A. ; Babaev, A. ; Backovic, S. ; Baghdasaryan, A. ; Baranov, P. ; Barrelet, E. ; Bartel, W. ; Baudrand, S. ; Baumgartner, S. ; Beckingham, M. ; Behnke, O. ; Behrendt, O. ; Belousov, A. ; Berger, N. ; Bizot, J.C. ; Boenig, M.-O. ; Boudry, V. ; Bracinik, J. ; Brandt, G.

Published in: Eur.Phys.J.
Year: 2006
Vol.: C48
Page No: 749-766
Pages: 33

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.

Total numbers of views: 1155
Numbers of unique views: 578
e-proceeding