Dual parametrization of the proton generalized parton distribution functions H and E, and description of the deeply virtual Compton scattering cross sections and asymmetries

We develop the minimal model of a new leading order parametrization of generalized parton distributions (GPDs) introduced by Polyakov and Shuvaev. The model for GPDs H and E is formulated in terms of the forward quark distributions, the Gegenbauer moments of the D-term, and the forward limit of the GPD E. The model is designed primarily for small and medium-size values of xB, xB≤0.2. We examine two different models of the t dependence of the GPDs: the factorized exponential model and the nonfactorized Regge-motivated model. Using our model, we successfully described the deeply virtual Compton scattering (DVCS) cross section measured by H1 and ZEUS, the moments of the beam-spin ALUsinφ, the beam-charge ACcosφ, and the transversely polarized target AUTsinφcosφ DVCS asymmetries measured by HERMES and ALUsinφ measured by CLAS. The data on ACcosφ prefer the Regge-motivated model of the t dependence of the GPDs. The data on AUTsinφcosφ indicate that the u and d quarks carry only a small fraction of the proton total angular momentum