Search

We present a physically motivated parametrization of the chiral-even generalized parton distributions in the nonsinglet sector obtained from a global analysis using a set of available experimental data. Our analysis is valid in the kinematical region of intermediate Bjorken x and for Q² in the multi-GeV region which is accessible at present and currently planned facilities. Relevant data included in our fit are from the nucleon elastic form factor measurements and from deep inelastic scattering experiments. Additional information provided by lattice calculations of the higher moments of generalized parton distributions is also considered. Recently extracted observables from deeply virtual Compton scattering on the nucleon are reproduced by our fit. [ABSTRACT FROM AUTHOR]

We provide the general expression of the cross section for exclusive deeply virtual photon electroproduction from a spin-1/2 target using current parametrizations of the off-forward correlation function in a nucleon for different beam and target polarization configurations up to twist-three accuracy. All contributions to the cross section including deeply virtual Compton scattering, the Bethe-Heitler process, and their interference, are described within a helicity-amplitude-based framework which is also relativistically covariant and readily applicable to both the laboratory frame and in a collider kinematic setting. Our formalism renders a clear physical interpretation of the various components of the cross section by making a connection with the known characteristic structure of the electron scattering coincidence reactions. In particular, we focus on the total angular momentum, Jz, and on the orbital angular momentum, Lz. On one side, we uncover an avenue to a precise extraction of Jz, given by the combination of generalized parton distributions, H+E, through a generalization of the Rosenbluth separation method used in elastic electron proton scattering. On the other side, we single out for the first time, the twist-three angular modulations of the cross section that are sensitive to Lz. The proposed generalized Rosenbluth technique adds constraints and can be extended to additional observables relevant to the mapping of the three-dimensional structure of the nucleon. [ABSTRACT FROM AUTHOR]