On chiral corrections to nucleon GPD

Abstract

Within the heavy baryon chiral perturbation theory we derive the leading chiral correction to the nucleon GPD at γ=0 . We discuss the difficulties of consideration non-local light-cone operators within heavy baryon approach and the methods to solve the difficulties. The consideration of the chiral corrections directly for non-local operators allows to resolve the ambiguity of the inverse Mellin transformation. In particular, we show that the mixing between axial and vector GPDs are of order m ²_π /M ² _N , which is two orders of magnitude less that it follows from the calculation of Mellin moments.