A bottom-up strategy to extract generalized parton distributions from experiment

We will present a bottom-up strategy to extract generalized parton distributions in the non-singlet sector from Deeply Virtual Compton Scattering data [1,2]. Our approach makes use of all available experimental information on both the proton and neutron form factors, and on the (inclusive) deep inelastic structure functions within a flexible parameterization based on a Regge-improved diquark model. Additional constraints provided by lattice calculations of the n=2,3 moments of generalized parton distributions are implemented through a reconstruction method based on orthogonal polynomials. $Q^2$ evolution, polynomiality, as well as a new set of constraints provided by dispersion relations [3] are also discussed. [1] S.~Ahmad, H.~Honkanen, S.~Liuti and S.~K.~Taneja, arXiv:0708.0268 [hep-ph]. [2] S.~Ahmad, H.~Honkanen, S.~Liuti and S.~K.~Taneja, Phys.\ Rev.\ D {\bf 75}, 094003 (2007) [3] M.~Diehl and D.~Y.~Ivanov, Eur.\ Phys.\ J.\ C {\bf 52}, 919 (2007)