Total hadronic cross-section of photon-photon interactions at OPAL

The total hadronic cross-section sigma /sub gamma gamma / for the interaction of real photons, gamma gamma to hadrons, is extracted from a measurement of the cross-section of the process e/sup +/e/sup -/ to e/sup +/e/sup -/ gamma * gamma * to e/sup +/e/sup -/+hadrons using a luminosity function for the photon flux and form factors for extrapolating to Q/sup 2/=0. The data was taken with the OPAL detector at LEP at e/sup +/e/sup -/ centre-of-mass energies square root (s/sub ee/)=161 GeV, 172 GeV and 183 GeV. In the energy range 10<or=W<or=110 GeV the total hadronic gamma gamma cross-section sigma /sub gamma gamma / is consistent with the Regge behaviour of the total cross-section observed in gamma p and hadron-hadron interactions. (23 refs).