Diffractive Electromagnetic Processes from a Regge Point of View

Abstract

The energy dependence of the cross sections for electromagnetic diffractive processes can be well described by a single power, $W^{\delta }$. For $J/\psi$ photoproduction this holds in the range from 20 GeV to 2 TeV. This feature is most easily explained by a single pole in the angular momentum plane which depends on the scale of the process, at least in a certain range of values of the momentum transfer. It is shown that this assumption allows a unified description of all electromagnetic elastic diffractive processes. We also discuss an alternative model with an energy dependent dipole cross section, which is compatible with the data up to 2 TeV and which shows an energy behaviour typical for a cut in the angular momentum plane.

Comments: 13 pages, 10 figures To be published in Physical Review D. arXiv admin note: substantial text overlap with arXiv:1503.06649 This article extends and replaces arXiv:1503.06649 . The present v2 only changes layout and organizes references with respect to v1