A phenomenological analysis of the nonperturbative QCD contributions for the photon wave function
Abstract
The photon  induced interactions, present in ep, eA, pp, pA, AA and e^{+}e^{} collisions, are expressed within the color dipole approach in terms of the photon wave function, which describes the transition of the photon into a quark  antiquark color dipole. Such quantity is usually calculated using perturbation theory assuming that long distance corrections associated to strong interactions can be neglected. In this paper we investigate the impact of these nonperturbative QCD (npQCD) corrections to the description of the photon wave function for dipoles of large size in several observables measured at HERA, LEP and LHC. We assume a phenomenological ansatz for the treatment of these npQCD corrections and constrain the free parameters of our model using the experimental data for the photoproduction cross section. The predictions for the γ γ cross section, exclusive ρ production in ep collisions and the rapidity distribution for the ρ production in PbPb collisions are compared with the data. We demonstrate that the inclusion of the nonperturbative QCD corrections improves the description of processes that are dominated by large dipoles.
 Publication:

European Physical Journal C
 Pub Date:
 June 2020
 DOI:
 10.1140/epjc/s1005202080432
 arXiv:
 arXiv:2003.11438
 Bibcode:
 2020EPJC...80..492G
 Keywords:

 High Energy Physics  Phenomenology;
 High Energy Physics  Experiment
 EPrint:
 8 pages, 6 figures. Improved version to be published in European Physical Journal C