Detailed QCD analysis of twist-3 effects in deeply virtual Compton scattering observables

摘要: In this paper I present a detailed QCD analysis of twist-3 effects in the Wandzura-Wilczek (WW) approximation deeply virtual Compton scattering (DVCS) observables for various kinematical settings, representing HERA, HERMES, CLAS and planned EIC (electron-ion-collider) experiments. find that WW are almost always negligible at collider energies but can be large low Q^2 smaller x_bj lower energy, fixed target experiments directly sensitive to real part DVCS amplitudes like charge asymmetry (CA). Conclusions then drawn about reliability extracting twist-2 generalized parton distributions (GPDs) from experimental data first, phenomenological, parameterization LO NLO GPD $H$, describing all currently available within errors is given.