Hadron annihilation into two photons and backward virtual Compton scattering in the scaling regime of QCD

We study the scaling regime of hadron-(anti)hadron annihilation into a deeply virtual photon and a real photon, H (H) over bar ->gamma(*)gamma, and backward virtual Compton scattering, gamma H-*-> H gamma. We advocate that there is a kinematical region where the scattering amplitude factorizes into a short-distance matrix element and a long-distance dominated object: a transition distribution amplitude which describes the hadron to photon transition.