Measurement of the hadronic cross-section for the scattering of two virtual photons at LEP

The interaction of virtual photons is investigated using the reaction hadrons based on data taken by the OPAL experiment at centre-of-mass energies GeV, for GeV and at an average of 17.9 GeV. The measured cross-sections are compared to predictions of the Quark Parton Model (QPM), to the Leading Order QCD Monte Carlo model PHOJET, to the NLO prediction for the reaction , and to BFKL calculations. PHOJET, NLO , and QPM describe the data reasonably well, whereas the cross-section predicted by a Leading Order BFKL calculation is too large. Received: 3 September 2001 / Published online: 5 April 2002