We study generalized parton distributions in the impact parameter representation, including the case of nonzero skewness ξ. Using Lorentz invariance, and expressing parton distributions in terms of impact parameter dependent wave functions, we investigate in which way they simultaneously describe longitudinal and transverse structure of a fast moving hadron. We compare this information with the...

We compare the contributions from quark and from gluon exchange to the exclusive process γ * p → ρ 0 p. We present evidence that the gluon contribution is substantial for values of the Bjorken variable x B around 0.1. 1. There is an ongoing experimental and theoretical effort to determine generalized parton distributions [1, 2] from hard exclusive processes like deeply virtual Compton scatterin...

We study large–distance contributions to the nucleon parton densities in the transverse coordinate (impact parameter) representation based on generalized parton distributions (GPDs). Chiral dynamics generates a distinct component of the partonic structure, located at momentum fractions x . Mπ/MN and transverse distances b ∼ 1/Mπ . We analyze the phenomenological “pion cloud” model of the flavor...

We present a simple empirical parameterization of the x-and t-dependence of generalized parton distributions at zero skewness, using forward parton distributions as input. A fit to experimental data for the Dirac, Pauli and axial form factors of the nucleon allows us to discuss quantitatively the interplay between longitudinal and transverse partonic degrees of freedom in the nucleon (" nucleon...

The process of deeply virtual Compton scattering will be shortly introduced, and the latest results from measurements at the HERA ep–collider at DESY will be given. In particular, the cross section has been measured with increased statistics at the collider experiments H1 and ZEUS, while HERMES for the first time reports measurements of the t–dependence of the beam–charge asymmetry on hydrogen ...