engleski

Fitting GPDs to DVCS Data: At Next-to-Leading-Order and Beyond

We outline the twist-two analysis of deeply virtual Compton scattering (DVCS) within the conformal partial wave expansion of the amplitude, represented as a Mellin--Barnes integral. The complete next-to-leading order results, including evolution, are obtained in the MS and a conformal factorization scheme. Within the latter, exploiting conformal symmetry, the radiative corrections are evaluated up to next-to-next-to- leading order. Using a new proposed parameterization for GPDs, we study the convergence of perturbation theory and demonstrate for H1 and ZEUS measurements that our formalism is suitable for a fitting procedure of DVCS observables. We also discuss the physical content of GPDs that is accessible in DVCS and is, to leading order, contained in the value on the cross-over trajectory.

generalized parton distributions; deeply virtual Compton scattering; next-to-next-to-leading order corrections; fitting procedure; conformal symmetry

nije evidentirano