Related papers: Parton content of the nucleon from distribution am…
Parton convolution models have been used extensively in describing the sea quarks in the nucleon and explaining quark distributions in nuclei (the EMC effect). From effective field theory point of view, we construct the parton convolution…
With a special intention of clarifying the underlying spin contents of the nucleon, we investigate the generalized form factors of the nucleon, which are defined as the $n$-th $x$-moments of the generalized parton distribution functions,…
We calculate the two-pion light-cone distribution amplitudes in the effective low-energy theory based on the instanton vacuum. These generalized distribution amplitudes describe the soft (non-perturbative) part of the process…
Collider data can play an important role in determining the parton distribution functions of the nucleon. I outline a formalism which makes it possible to use next-to-leading order calculations in such an extraction, while minimizing the…
We extend the investigation of the Generalized Parton Distribution for a charged pion within a fully covariant constituent quark model, in two respects: (i) calculating the tensor distribution and (ii) adding the treatment of the evolution,…
The partonic structure of hadrons plays an important role in a vast array of high-energy and nuclear physics experiments. It also underpins the theoretical understanding of hadron structure. Recent developments in lattice QCD offer new…
We present a consistent calculation of the structure functions within a light-front constituent quark model of the nucleon. Relativistic effects and the relevance of the covariance constraints are analyzed for both polarized and unpolarized…
We discuss what can be learned about the shape of the pion distribution amplitude from the form factor for gamma* gamma(*) to pi transitions.
Many approaches to nucleon-nucleus elastic and inelastic scattering are based on the use of the free-space nucleon-nucleon transition amplitude. In calculations where the full spin-dependence of this amplitude is needed, its use is more…
The current status of global QCD analysis of parton distribution functions of the nucleon is reviewed. Recent progress made in determining various features of the parton structure of the nucleon, as well as outstanding open questions are…
We study the low $Q^2$ wave-functions of pions and kaons as an expansion in terms of hadron-like Fock state fluctuations. In this formalism, pion and kaon wave-functions are related one another. Consequently, the knowledge of the pion…
The QCDSF/UKQCD collaboration has an ongoing program to calculate nucleon matrix elements with two flavours of dynamical O(a) improved Wilson fermions. Here we present recent results on the electromagnetic form factors, the quark momentum…
We summarize results from our recent paper* on nucleon Compton scattering in the Dyson-Schwinger approach. We study the Compton scattering phase space and its various kinematic limits, and we introduce a covariant, transverse tensor basis…
The leading chiral contributions to the quark and gluon components of the proton spin are calculated using heavy-baryon chiral perturbation theory. Similar calculations are done for the moments of the generalized parton distributions…
We present a systematic study of twist three light-cone distribution amplitudes of vector mesons in QCD, which is based on conformal expansion and takes into account meson and quark mass corrections. A complete set of distribution…
We present a lattice-QCD calculation of the pion, kaon and $\eta_s$ distribution amplitudes using large-momentum effective theory (LaMET). Our calculation is carried out using three ensembles with 2+1+1 flavors of highly improved staggered…
The invariant amplitudes for pion electroproduction on the nucleon are evaluated by dispersion relations at constant t with MAID as input for the imaginary parts of these amplitudes. In the threshold region these amplitudes are confronted…
Based on both the constituent quark picture and the instanton model for QCD vacuum, we calculate the unpolarized and polarized gluon distributions in the constituent quark and in the nucleon. Our approach consists of the two main steps. At…
The properties of nuclear matter and finite nuclei are studied within the quark mean field (QMF) model by taking the effects of pion and gluon into account at the quark level. The nucleon is described as the combination of three constituent…
Generalized parton distributions describe the distribution of partons in the transverse plane. For transversely polarized quarks and/or nucleons, these impact parameter dependent parton distributions are not axially symmetric. These…