COLOR DIPOLE BFKL-REGGE FACTORIZATION AND HIGH-ENERGY PHOTON-PHOTON SCATTERING
Nikolaev N.N., Speth J., Zoller V.R.

Received: June 25, 2001

PACS: 12.38.-t, 13.60.Hb, 13.85.Lg

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Based on the color dipole representation, we investigate consequences for the γ^*γ^*,γ^*γ scattering of the finding by Fadin, Kuraev, and Lipatov that the incorporation of asymptotic freedom into the BFKL equation makes the QCD pomeron a series of isolated poles in the angular momentum plane. The emerging color dipole BFKL-Regge factorization allows us to relate in a model-independent way the contributions of each BFKL pole to the γ^*γ^*,γ^* γ scattering and the deep inelastic scattering on protons. Numerical predictions based on our early work on the color dipole BFKL phenomenology of the deep inelastic scattering on protons gives a good agreement with the recent experimental data from OPAL and L3 experiments at LEP200. We discuss the role of nonperturbative dynamics and predict a pronounced effect of the Regge-factorization breaking due to large unfactorizable nonperturbative corrections to the perturbative vacuum exchange. We comment on the salient features of the BFKL-Regge expansion for the γ^*γ^*,γ^*γ scattering including the issue of the decoupling of subleading BFKL poles and the soft plus rightmost hard BFKL pole dominance.