Diffraction dissociation in photoproduction at HERA

Journal article

A study is presented of the process γp → XY, where there is a large rapidity gap between the systems X and Y. Measurements are made of the differential cross section as a function of the invariant mass Mx of the system produced at the photon vertex. Results are presented at centre of mass energies of (W) = 187 GeV and 〈W〉 = 231 GeV, both where the proton dominantly remains intact and, for the first time, where it dissociates. Both the centre of mass energy and the Mx 2 dependence of HERA data and those from a fixed target experiment may simultaneously be described in a triple-Regge model. The low mass photon dissociation process is found to be dominated by diffraction, though a sizable subleading contribution is present at larger masses. The pomeron intercept is extracted and found to be αP(0) = 1.068 ± 0.016 (stat.) ± 0.022 (syst.) ± 0.041 (model), in good agreement with values obtained from total and elastic hadronic and photoproduction cross sections. The diffractive contribution to the process γp → Xp with Mx 2/W2 < 0.05 is measured to be 22.2 ± 0.6 (stat.) ± 2.6 (syst.) ± 1.7 (model) % of the total γp cross section at 〈W〉 = 187 GeV. © Springer-Verlag 1997.

Authors: Adloff, C; Aid, S; Anderson, M; Andreev, V; Andrieu, B

• Publication status: Published
• Journal: ZEITSCHRIFT FUR PHYSIK C-PARTICLES AND FIELDS
• Volume: 74
• Issue: 2
• Pages: 221-235
• Publication date: 1997-04-01
• DOI: 10.1007/s002880050385
• EISSN: 1431-5858
• ISSN: 0170-9739