Unifying “soft” and “hard” diffractive exclusive vector meson production and deeply virtual Compton scattering

Abstract

A Pomeron model applicable to both ``soft'' and ``hard'' processes is suggested and tested against the high-energy data from virtual photon-induced reactions. The Pomeron is universal, containing two terms, a soft and a hard one, whose relative weight varies with $\stackrel{\texttildelow{}}{{Q}^{2}}={Q}^{2}+{M}_{V}^{2}$, where ${Q}^{2}$ is the virtuality of the incoming photon and ${M}_{V}$ is the mass of the produced vector particle. With a small number of adjustable parameters, the model fits all available data on vector meson production and deeply virtual Compton scattering from HERA. Furthermore, we attempt to apply the model to hadron-induced reactions, by using high-energy data on proton-proton scattering.