Complex conformal spin partial wave expansion of generalized parton distributions and distribution amplitudes

We introduce a new representation of generalized parton distributions and generalized distribution amplitudes that is based on the partial wave decomposition with respect to the complex collinear conformal spin. This decomposition leads us to a versatile parameterization of these non-perturbative functions in terms of conformal moments, which are measurable for integer value on the lattice. This new representation has several advantages: basic properties and crossing relations are automatically implemented, a rather flexible parameterization is possible, the numerical treatment of evolution is simple and analytic approximation of scattering amplitudes can be given. We demonstrate this for simple examples. In particular, phenomenological considerations indicate that the t-dependence of Mellin moments is governed by Regge trajectories. The new representation is vital to push the analysis of deeply virtual Compton scattering to next-to-next-to-leading order.Comment: 66 pages, 11 figures, 1 tabl

A lower bound for the density of states of the lattice Anderson model

We consider the Anderson model on the multi-dimensional cubic lattice and prove a positive lower bound on the density of states under certain conditions. For example, if the random variables are independently and identically distributed and the probability measure has a bounded Lebesgue density with compact support, and if this density is essentially bounded away from zero on its support, then we prove that the density of states is strictly positive for Lebesgue-almost every energy in the deterministic spectrum.Comment: 7 pages, typos corrected in v2, to appear in Proc. Amer. Math. So

Nucleon hologram with exclusive leptoproduction

Hard exclusive leptoproductions of real photons, lepton pairs and mesons are the most promising tools to unravel the three-dimensional picture of the nucleon, which cannot be deduced from conventional inclusive processes like deeply inelastic scattering.Comment: 9 pages LaTeX, 7 figures, sign in Eq. (16) corrected, Invited talk at the European Workshop "QCD structure of the nucleon", Ferrara, Italy, April 3-6, 200

Radiative corrections to deeply virtual Compton scattering

We discuss possibilities of measurement of deeply virtual Compton scattering amplitudes via different asymmetries in order to access the underlying skewed parton distributions. Perturbative one-loop coefficient functions and two-loop evolution kernels, calculated recently by a tentative use of residual conformal symmetry of QCD, are used for a model dependent numerical estimation of scattering amplitudes.Comment: 9 pages LaTeX, 3 figures, czjphyse.cls required Talk given by D. M\"uller at Inter. Workshop ``PRAHA-Spin99'', Prague, Sept. 6-11, 199

Factorization in hard diffraction

In this talk, I reviewed the role of factorization in diffraction hard scattering.Comment: Talk presented at the Ringberg Workshop on ``New Trends in HERA Physics 2001''. 10 pages, 6 postscript figures. Misprints correcte