gamma*gamma* reactions at high energies

The total hadronic gamma*gamma* cross sections at high energy are calculate d as a function of energy and photon virtuality in a model combining Reggeo n exchange, the quark box diagram (a fixed pole in Regge language) and soft and hard pomeron exchanges evaluated in the context of dipole-dipole scatt ering. Goad agreement is obtained with the data for the real gamma gamma cr oss section and for the real photon structure function F-2(gamma). However the model prediction for the gamma*gamma* cross section is too small. This is attributed to an incorrect extrapolation of the Q(2) dependence of the h ard pomeron adopted here. Parametrising it independently shows that the har d part of the cross section can be well represented by a simple Regge pole with intercept similar to 1.3.