Related papers: Parton Distribution within Virtual Particles and $…
We study deeply virtual Compton scattering on a virtual pion that is emitted by a proton. Using a range of models for the generalized parton distributions of the pion, we evaluate the cross section, as well as the beam spin and beam charge…
A model for deeply virtual Compton scattering, based on analytical light-cone hadron wave functions is presented and studied at energies currently accessible at Jefferson Laboratory, DESY, and beyond. It is shown that perpendicular vector…
A simple model of a composite nucleon is developed in which a fermion and a boson, representing quark and diquark constituents of the nucleon, form a bound state owing to a contact interaction. Photon and pion couplings to the quark provide…
The manifestations of QCD effects on quark and gluon distribution functions of longitudinally polarized virtual photons involved in hard collisions are investigated. It is shown that for moderate photon virtualities and in the kinematical…
The deeply virtual Compton scattering reaction has been investigated in the Hall A of the Jefferson Laboratory by measuring longitudinally polarized (e,e'gamma) cross sections, in the valence quark region, for protons and neutrons. In the…
Using a quark model, we calculate symmetry breaking effects in the valence quark distributions of the nucleon. In particular, we examine the breaking of the quark model SU(4) symmetry by color magnetic effects, and find that color magnetism…
We give a complete representation of virtual Compton scattering $\gamma^* p \to \gamma p$ at large initial photon virtuality $Q^2$ and small momentum transfer squared $t$ in terms of the light-cone wavefunctions of the target proton. We…
We re\,examine the theory of hadronic photon-nucleon interactions at the quark-gluon level. The possibility of multiple parton collisions in a single photon-nucleon collision requires an eikonal treatment of the high-energy scattering…
Hadrons are composite objects made of quarks and gluons, and during a collision one can have several elementary interactions between the constituents. These elementary interactions, using an appropriate theoretical framework, can be related…
Here the probability density of relativistic particles coordinates, satisfying the formal conditions of the quantum mechanics and the special relativity, is determined (under textbooks view, such density does not exist). It is specified for…
The parton distribution functions determined by CTEQ at low $Q^2$ are used as inputs to test the validity of the valon model. The valon distributions in a nucleon are first found to be nearly $Q$ independent. The parton distribution in a…
We present a model for the structure of baryons in which the valence partons interact through a linear potential. This model can be derived from QCD in the approximation where transverse momenta are ignored. We compare the valence quark…
The amplitudes for virtual Compton scattering off protons are calculated within the framework of the diquark model in which protons are viewed as being built up by quarks and diquarks. The latter objects are treated as quasi-elementary…
The pion structure function is investigated in a simple model, where the pion and its constituent quark fields are coupled through the simplest pseudoscalar coupling. The imaginary part of the forward gamma* pi -> gamma* pi scattering…
We consider double parton distributions in the general case in which the virtualities of the interacting partons are different. We elaborate the corresponding evolution equations and their extension to next-to-leading logarithmic accuracy.
A model for the $p(e,e'\pi^+)n$ reaction which combines an improved treatment of gauge invariant meson--exchange currents and hard deep--inelastic scattering (DIS) of virtual photons off nucleons is proposed. It is shown that DIS dominates…
Although quantum correlations in a quantum system are characterized by the evolving quantities (which are entanglement and discord usually), we reveal such basis (i.e. the set of virtual particles) for the representation of the density…
Parton distributions in impact parameter space, which are obtained by Fourier transforming GPDs, exhibit a significant deviation from axial symmetry when target and/or quark are transversely polarized. In combination with the final state…
The HERMES collaboration has recently published a set of (correlated) beam charge, beam spin and target spin relative asymmetries for the Deeply Virtual Compton Scattering process. This reaction allows in principle to access the Generalized…
Valence u- and d-quarks distributions in proton are calculated in QCD at low $Q^2$ and intermediate x, basing on the operator product expansion (OPE). The imaginary part of the virtual photon scattering amplitude on quark current with…