Author/Authors :
Q2) Original Research Article
Pages 471-502
H1 Collaboration، نويسنده , , J. C. Adloff، نويسنده , , A. V. Andreev، نويسنده , , B. Andrieu، نويسنده , , T. Anthonis، نويسنده , , V. Arkadov، نويسنده , , A. Astvatsatourov، نويسنده , , I. Ayyaz، نويسنده , , A. Babaev and NRMI Investigators، نويسنده , , Matthias J. Bahr، نويسنده , , P. Baranov، نويسنده , , E. Barrelet، نويسنده , , W. Bartel، نويسنده , , P. Bate، نويسنده , , A. Beglarian، نويسنده , , O. Behnke، نويسنده , , C. Beier، نويسنده , , V. A. Belousov، نويسنده , , T. Benisch، نويسنده , , Ch. Berger، نويسنده , , et al.، نويسنده ,
Abstract :
The total cross section for the photoproduction process with a leading proton in the final state has been measured at γp centre-of-mass energies W of 91, 181 and 231 GeV. The measured cross sections apply to the kinematic range with the transverse momentum of the scattered proton restricted to pT⩽0.2 GeV and 0.68⩽z⩽0.88, where z=Ep′/Ep is the scattered proton energy normalised to the beam energy. The cross section dσγp→Xp′(W,z)/dz is observed to be independent of W and z within the measurement errors and amounts to (8.05±0.06 (stat)±0.89 (syst)) μb on average. The data are well described by a Triple Regge model in which the process is mediated by a mixture of exchanges with an effective Regge trajectory of intercept αi(0)=0.33±0.04 (stat)±0.04 (syst). The total cross section for the interaction of the photon with this mixture (γαi→X) can be described by an effective trajectory of intercept αk(0)=0.99±0.01 (stat)±0.05 (syst). Predictions based on previous triple Regge analyses of pp→pX data assuming vertex factorisation are broadly consistent with the γp data. The measured cross sections are compared with deep inelastic scattering leading proton data in the same region of z and pT for photon virtuality Q2>2.5 GeV2. The ratio of the cross section for leading proton production to the total cross section is found to rise with Q2.
