Compton scattering beyond impulse approximation: Correlation, nonlocal-exchange and dynamic effects

A new approach is proposed in treating doubly differential cross section (differential in outgoing photon energy and angle) for Compton scattering of a photon from an NN-electron many-body state. In this approach, the usual impulse approximation (IA) is generalized to include dynamic effects as well as correlations and nonlocal exchange corrections. By including correlations the approach goes beyond independent particle approximation (IPA). We apply the main approach of IA (IA serves to interpret Compton scattering measurements in terms of electron momentum distribution in the target) but understanding IA as just a special case of a more general description in which electrons are bound but with a certain distribution of the IPA states.