Kirill Semenov-Tian-Shansky (PNPI)


On the equivalence of phenomenological representations of generalized parton distributions


Phenomenological representations of generalized parton distributions (GPDs) implementing the non-trivial field theoretical requirements are employed in the present day strategies for extracting of hadron structure information encoded in GPDs from the observables of hard exclusive reactions. I will consider the mathematical aspects of establishing equivalence between the dual parametrization of GPDs and the Mellin-Barnes integral approach, which are the two frameworks for handling the double partial wave (PW)expansion of GPDs in the conformal partial waves and in the cross-channel SO(3) partial waves. I will present the relation between the GPD representations based on the conformal PW expansion and the double distribution representation of A.Radyushkin. I will also discuss the J=0 fixed pole universality hypothesis of S.Brodsky and the relation between the J=0 fixed pole contribution into the Compton scattering amplitude and the D-term form factor