Towards a global analysis of generalized parton distributions

We discuss the complexity of GPD phenomenology, comment on the technological needs for a global analysis, and report on model and neural network fits to the photon electroproduction off unpolarized proton. We also point out that Radyushkin's double distribution ansatz is a `holographic' GPD model.Comment: LaTeX, 12 pages, 3 figures, proceedings of the "4th Workshop on Exclusive Reactions at High Momentum Transfer", TJNAF, May 18-21, 2010, plus additional references and footnote

The Isgur-Wise Function within a Modified Heavy-Light Chiral Quark Model

We consider the Isgur-Wise function xi(omega) within a new modified version of a heavy-light chiral quark model. While early versions of such models gave too small absolute value of the slope, namely xi'(1) of about -0.4 to -0.3, we show how extended version(s) may lead to values around -1, in better agreement with recent measurements. This is obtained by introducing a new mass parameter in the heavy quark propagator. We also shortly comment on the consequences for the decay modes B --> D D-bar.Comment: 20 pages, 7 PS figure, LaTe

Revealing CFFs and GPDs from experimental measurements

We report on the status of the phenomenological access of generalized parton distributions from photon and meson electroproduction off proton. Thereby, we emphasize the role of HERMES data for deeply virtual Compton scattering, which allows us to map various asymmetries into the space of Compton form factors.Comment: 7 pages, 2 figure

New Dipole Penguin Contribution to K --> pi pi decays

We point out that the standard chromomagnetic penguin dipole operator has a counterpart corresponding to off-shell momenta for external quarks. By employing the chiral quark model, we show that this new dipole penguin operator has the same bosonisation as the standard Q_6 operator. Accordingly, this new operator enlarges by ~ 5 % the referent Q_6 contribution, which gives the dominant contribution to the CP-violating ratio epsilon'/epsilon and also gives an important contribution to the Delta I = 1/2 amplitude.Comment: 17 pages, 1 PS figure, LaTeX, corresponds to published versio