Q2dependence of exclusive baryon-antibaryon production in photon-photon collisions

We compute the cross sections for baryon-antibaryon production in photon-photon reactions in which one or both of the photons is off shell, i.e., virtual. Besides confirming the $Q^2$→0 limits obtained previously by Farrar we demonstrate that the $Q^2$ dependence of the cross sections provides dramatic further tests of QCD and of the factorization formalism underlying the application of QCD to these reactions. In particular the $Q^2$ dependence is very sensitive to the baryon wave functions that are folded together with the hard-scattering quark-level tree graphs.