Pion Generalized Distribution Amplitudes in the Nonlocal Chiral Quark Model

Abstract

We use a simple, instanton motivated, nonlocal chiral quark model to calculate pion Generalized Distribution Amplitudes (GDAs). The nonlocality appears due to the momentum dependence of the constituent quark mass, which we take in a form of a generalized dipole formula. With this choice all calculations can be performed directly in the Minkowski space and the sensitivity to the shape of the cutoff function can be studied. We demonstrate that the model fulfills soft pion theorems both for chirally even and chirally odd GDAs. The latter one cannot be derived by the methods of current algebra. Whenever possible we compare our results with the existing data. This can be done for the pion electromagnetic form factor and quark distributions as measured in the proton-pion scattering.