Two Photon Reactions at High Energies
  Cross sections for the reactions gamma^(*) gamma^(*) --> hadrons and gamma^(*) gamma^(*) --> 2 vector mesons are calculated as functions of energy (sqrt(s) > 20 GeV) and photon virtualities. Good agreement with experiment is obtained for the total hadronic cross section and, after allowing for a valence-quark contribution from the hadronic part of the photon, with the photon structure function at small x. The cross section for vector meson production are shown to be experimentally accessible for moderate values of Q^2. This is sufficient to probe the nature of the hard pomeron which has recently been proposed. 
A. Donnachie (1), H.G. Dosch (2), Michael Rueter (3) ((1) University   of Manchester, (2) Universitaet Heidelberg, (3) Tel-A...