Probing the QCD pomeron in high-energy ${\gamma }^{\ast }{\gamma }^{\ast }$ collisions

Abstract

Based on the color dipole representation, we investigate consequences for the ${\gamma }^{\ast }{\gamma }^{\ast },{\gamma }^{\ast }\gamma$ scattering of the finding by Fadin, Kuraev and Lipatov that incorporation of asymptotic freedom into the BFKL equation makes the QCD pomeron a series of isolated poles in the angular momentum plane. We present parameter-free predictions for the vacuum exchange contribution to the photon structure function which agree well with OPAL and L3 determinations. A good agreement is found between our predictions for the energy and photon virtuality dependence of the photon-photon cross section ${\sigma }^{{\gamma }^{\ast }{\gamma }^{\ast }}(W,Q^2,P^2)$ and the recent data taken by the L3 Collaboration.

Comments: 5 pages Latex + 2 Figures EPS