Photon diffractive dissociation in deep-inelastic scattering

This paper is mainly devoted to the presentation and discussion of formulas for the cross section of photon diffractive dissociation. The calculations which we present in a very detailed way are based on perturbative QCD. We improve formulas which describe this process in the triple Regge limit where the square of the missing mass MX (the invariant mass of the bunch of secondary hadrons) is much larger than Q2 and extend the range of validity to the region where MX2 is of the same order as Q2. We introduce a diffractive dissociation structure function and show that it obeys the Gribov-Lipatov-Altarelli-Parisi evolution equation, but, with an additional inhomogeneous term. The relation to the Pomeron structure function is discussed.