A model for the off-forward structure functions of the pion

AbstractWe extend our model for the pion, which we used previously to calculate its diagonal structure function, to the off-forward case. The imaginary part of the off-forward γ★π→γ★π scattering amplitude is evaluated in the chiral limit (mπ=0) and related to the twist-two and twist-three generalised parton distributions H, H3, H̃3. Non-perturbative effects, linked to the size of the pion and still preserving gauge invariance, are included. Remarkable new relations between H, H3 and H̃3 are obtained and discussed