EPOS is a new energy conserving multiple scattering approach based on partons and Pomerons (parton ladders), with special emphasis on high parton densities. The latter aspect, particularly important in proton-nucleus or nucleus-nucleus collisions, is taken care of via an effective treatment of Pomeron-Pomeron interactions. Soft and hard interactions are treated in a consistent way. EPOS is the ...

We compute amplitude of deeply virtual Compton scattering in the parton model. We found that the amplitude in the hard regime up to the accuracy O(1/Q) depends on new skewed parton distributions (SPD's). These additional contributions make the DVCS amplitude explicitly transverse. The new SPD's contribute to various spin, charge and azimuthal asymmetries at the same order in 1/Q as the leading ...

Over the past years a lot of progress has been made in the understanding of single spin asymmetries in hard scattering processes. We briefly review this subject, covering the non-vanishing of time-reversal odd parton distributions, universality of fragmentation functions, and the discovery of previously unknown timereversal odd parton distributions at subleading twist. Interestingly enough, all...

The 1994 data published by the H1 collaboration are compared with models based on Regge phenomenology. The xIP dependence of the data can be described in a model based on the exchange of a dominant diffractive (pomeron) trajectory with additional sub-leading reggeon contributions. The dynamics of the Pomeron structure is studied within the framework of perturbative QCD and new parton distributi...