Hard diffraction with dynamic gap survival

We present a new framework for the modelling of hard diffraction in pp and p (p) over bar collisions. It starts from the the approach pioneered by Ingelman and Schlein, wherein the single diffractive cross section is factorized into a Pomeron flux and a Pomeron PDF. To this it adds a dynamically calculated rapidity gap survival factor, derived from the modelling of multiparton interactions. This factor is not relevant for diffraction in ep collisions, giving non-universality between HERA and Tevatron diffractive event rates. The model has been implemented in PYTHIA 8 and provides a complete description of the hadronic state associated with any hard single diffractive process. Comparisons with pp and pp data reveal improvement in the description of single diffractive events.