The hadronic structure of the photon and the space-time behavior of its interactions

The study of hadron-mediated high-energy photon interactions is continued, with emphasis on their space-time development. A formalism is developed which distinguishes these from direct photon interactions, and the concept of formation time is discussed. It is shown that hadron-mediated interactions have the appropriate long-range behaviour required by the usual space-time treatment in accounting for the diffractive region. It is described how hadron-mediated interactions can lead to scaling (outside the context of specific models), and the relationship to the parton model is indicated. (Auth.)