Crossed channel analysis of quark and gluon generalized parton   distributions with helicity flip
  Quark and gluon helicity flip generalized parton distributions (GPDs) address the transversity quark and gluon structure of the nucleon. In order to construct a theoretically consistent parametrization of these hadronic matrix elements, we work out the set of combinations of those GPDs suitable for the ${\rm SO}(3)$ partial wave (PW) expansion in the cross-channel. This universal result will help to build up a flexible parametrization of these important hadronic non-perturbative quantities, using for instance the approaches based on the conformal PW expansion of GPDs such as the Mellin-Barnes integral or the dual parametrization techniques. 
B. Pire, K. Semenov-Tian-Shansky, L. Szymanowski, S. Wallon
hep-ph nucl-ex nucl-th