Hard Meson Electroproduction Research Articles

Generalized parton distributions

We discuss how generalized parton distributions (GPDs) enter in a variety of hard exclusive processes such as deeply virtual Compton scattering (DVCS) and hard meson electroproduction reactions on the nucleon. We show some key observables which are sensitive to the various hadron structure aspects of the GPDs, and discuss their experimental status.

Generalized parton distributions and hard exclusive reactions

We discuss how generalized parton distributions (GPDs) enter in a variety of hard exclusive processes such as deeply virtual Compton scattering (DVCS) and hard meson electroproduction reactions on the nucleon. We discuss the links between GPDs and elastic nucleon form factors as well as the information contained in the second moment of GPDs. We subsequently show some key observables which are sensitive to the various hadron structure aspects of the GPDs, and discuss their experimental status.

Overview on all reactions linked to GPDs

A short overview is given on how generalized parton distributions (GPDs) enter in a variety of hard exclusive processes such as deeply virtual Compton scattering (DVCS) and hard meson electroproduction reactions on the nucleon. We firstly discuss the links between GPDs and elastic nucleon form factors which represent powerful constraints on parametrizations of GPDs. Subsequently, we show some key observables which are sensitive to the various hadron structure aspects of the GPDs, and which are at present under experimental investigation at different facilities (HERMES, H1/ZEUS, JLab and Compass), or will be addressed by experiments in the near future.

Probing the nucleon at large momentum transfer

The central role of soft nucleon matrix elements in reactions of high energy electrons or real photons with nucleons is emphasized. These soft matrix elements are described in terms of skewed parton distributions. Their connections to ordinary parton distributions, form factors, Compton scattering and hard meson electroproduction is discussed.

Deeply virtual electroproduction of photons and mesons on the nucleon

We give predictions for the leading order amplitudes for deeply virtual Compton scattering and hard meson electroproduction reactions at large Q^2 in the valence region in terms of skewed quark distributions. We give first estimates for the power corrections to these leading order amplitudes. In particular, we outline examples of experimental opportunities to access the skewed parton distributions at the current high-energy lepton facilities : JLab, HERMES and COMPASS.

Exclusive electroproduction of vector mesons, pseudoscalar mesons and photons in the Bjorken regime

Deeply virtual Compton scattering (DVCS) and the exclusive electroproduction of vector mesons (ϱ 0 , ϱ ± , ω, ) and pseudoscalar mesons (π 0 , π ± , …) in the Bjorken regime are sensitive to the recently introduced off-forward parton distributions. We calculate the leading order amplitudes for DVCS and hard meson electroproduction reactions in the valence region and use a model ansatz for the OFPD's to give estimates of observables relevant for experiments at COMPASS, HERMES and JLAB.