Quark and gluon helicity flip generalized parton distributions (GPDs) encode
the information on the nucleon structure in the transversity sector. In order
to build a theoretically consistent phenomenological parametrization for these
hadronic matrix element within the framework of the dual parametrization of
GPDs (or with the equivalent approach of the SO(3) partial waves (PW) expansion
with the Mellin-Barnes integral techniques) we establish the set of
combinations of parton helicity flip GPDs suitable for the expansion in the
cross channel SO(3) PWs.Comment: 6 pages, DIS 2014, XXII. International Workshop on Deep-Inelastic
Scattering and Related Subjects, 28 April - 2 May 2014, Warsaw, Polan
