  We study the scaling regime of hadron-(anti)-hadron annihilation into a
deeply virtual photon and a real photon, H anti-H -> gamma^* gamma, and deep
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.
