We review the recent progress of the theoretical understanding of the spin structure of the nucleon based on Heavy Baryon Chiral Perturbation Theory (HBChPT). At low Q2 the spin structure of the nucleon is encoded into the generalized spin polarizabilities (spin GP's) extracted from the virtual Compton scattering (VCS) amplitudes. The spin GP's of the nucleon have been calculated up to next-to-leading order in HBChPT. Furthermore, the forward spin generalized polarizabilities, which are related to the nucleon polarized structure functions g1 and g2 through the sum rules based on dispersion relations, also have been calculated in HBChPT up to next-to-leading order. As a summary, the physics content of the existing data is discussed and some perspectives for future theoretical and experimental activities in this field are also presented.
Higher moments of nucleon spin structure functions in heavy baryon chiral perturbation theory and in a resonance model
