A PARTON MODEL FOR DIFFRACTIVE PROCESSES IN DEEP-INELASTIC SCATTERING

We demonstrate that the global properties of the ''rapidity gap'' events, observed at HERA, can be understood based on electron-gluon scattering as the underlying partonic process. Using the measured inclusive structure function F-2 to determine the parameters of the parton model, the diffractive structure function F-2(D) is predicted. The ratio of diffractive and inclusive cross sections, R(D) = sigma(D)/sigma(incl)similar or equal to 1/9, is determined by the probability of the produced quark-antiquark pair to evolve into a colour singlet state. This colour singlet cluster may fragment into hadrons independently of the proton remnant, yielding the observed gap in rapidity.