Related papers: Transition Distribution Amplitudes : from JLab to …
We present an exploratory study using generalized parton distributions of several observables related to transverse degrees of freedom in hadronic structure -- the nucleon transverse momentum, the transverse radius, or impact parameter, and…
The study of the two-body photodisintegration of the deuteron in the few GeV region is the ideal reaction to clarify the transition from the nucleonic degrees of freedom to the QCD picture of hadrons. The CLAS large angle spectrometer of…
Generalized Parton Distributions of the pion are evaluated in chiral quark models with the help of double distributions. As a result the polynomiality conditions are automatically satisfied. In addition, positivity constraints, proper…
The field of Generalized Parton Distribution (GPD) benefited from a wealth of exclusive reactions measurements since 2000. Extraction of GPDs from observables has begun with this first generation of experiments. In the short and mid-term…
Hadron structure calculations using lattice Quantum Chromodynamics (QCD) have advanced significantly in recent years. Results for charges, form factors, and lower Mellin moments can be obtained to high precision, generalized parton…
We consider the reactions gamma p --> M B, with M B being either K+ Lambda, K+ Sigma0, or Pi n, within a diquark model which is based on perturbative QCD. The model parameters and the quark-diquark distribution amplitudes of the baryons are…
We study the analytic structure of partial-wave amplitudes derived from u- and t-channel exchange processes. The latter plays a crucial role in dispersion-theory approaches to coupled-channel systems that model final state interactions in…
We study in the framework of collinear QCD factorization the photoproduction of a $\gamma\,\pi$ pair with a large invariant mass and a small transverse momentum, as a new way to access generalized parton distributions. In the kinematics of…
The relativistic amplitudes of pion photoproduction are evaluated by dispersion relations at t=const. The imaginary parts of the amplitudes are taken from the MAID model covering the absorption spectrum up to center-of-mass energies W = 2.2…
Over the past two decades, meson photo- and electro-production data of unprecedented quality and quantity have been measured at electromagnetic facilities worldwide. By contrast, the meson-beam data for the same hadronic final states are…
Transition generalized parton distributions (GPDs) describe matrix elements of nonlocal partonic QCD operators between the ground and excited baryon states and provide new tools for quantifying and interpreting the structure of baryon…
The calculation of baryon wave functions at small inter-quark separations is an ongoing effort within the QCDSF collaboration. In this update on normalization constants and distribution amplitudes of the nucleon and its negative parity…
A new Hamiltonian model is introduced to study the spectrum of light hadrons. It combines relativistic field theory with elements of the constituent quark model. In addition to the standard linear confining and pseudoscalar meson exchange…
The diffractive electro- or photo-production of two mesons separated by a large rapidity gap gives access to generalized parton distributions (GPDs) in a very specific way. First, these reactions allow to easily access the chiral-odd…
We study the structure of generalized parton distributions in impact parameter space with the aim of determining the size and role of small transverse separations components in the quarks wave function. We analyze the relation between…
Electron Ion Collider is a future high energy facility for studies of the structure of the nucleon. Three-dimensional parton structure is one of the main goals of EIC. In momentum space Transverse Momentum Dependent Distributions (TMDs) are…
The 1/N_c expansion of QCD provides a valuable semiquantitative tool to study baryon scattering amplitudes and the short-lived baryon resonances embedded within them. A generalization of methods originally applied in chiral soliton models…
Meson photoproduction is an important tool in the study of baryon resonances. The spectrum of broad and overlapping nucleon excitations can be greatly clarified by use of polarization observables. The N* program at Jefferson Lab with the…
The J-PARC facility is near completion and experiments will start in 2009 on nuclear and particle physics projects. In this article, the J-PARC facility is introduced, and possible projects are discussed in high-energy hadron physics by…
Chiral symmetry is one of the most fundamental symmetries in QCD. It is closely connected to hadron properties in the nuclear medium via the reduction of the quark condensate <bar{q}q>, manifesting the partial restoration of chiral…