Related papers: Proton spin structure and quark-parton model
It is shown that in the special infinite momentum frame where photon has pure transverse components at $P\rightarrow\infty$ the spin-dependent deep inelastic structure function $ g_{2}(x)$ has a reasonable interpretation in terms of…
We review the present understanding of the spin structure of protons and neutrons, the fundamental building blocks of nuclei collectively known as nucleons. The field of nucleon spin provides a critical window for testing Quantum…
Transverse parton momentum dependent distribution functions (TMDs) of the nucleon are studied in a covariant model, which describes the intrinsic motion of partons in terms of a covariant momentum distribution. The consistency of the…
An unified scheme for describing both spin and orbital motion in symmetry-breaking chiral quark model is suggested. The analytic results of the spin and orbital angular momenta carried by different quark flavors in the nucleon are given.…
We discuss the implications of a "constituent quark" structure of the nucleon for the leading (1/Q^2-) power corrections to the spin structure functions. Our basic assumption is the presence of quark-gluon correlations in the nucleon wave…
We present a quark-parton model to describe polarized and unpolarized nucleon structure functions. The twist-two matrix elements for the QCD evolution analysis of lepton-hadron scattering are calculated within a light-front covariant quark…
The spin structure function $g_1^p$ of the proton is studied in a two component framework, where the perturbative evolution of parton distributions and nonperturbative vector meson dominance model are used. We predict the $g_1^p$ asymmetric…
A brief summary on the Wigner rotation effect in the understanding of the proton spin ``crisis" related with the Ellis-Jaffe sum rule violation, and on the proton-neutron isospin symmetry breaking explanation of the Gottfried sum rule…
We present a study of proton and neutron electromagnetic form factors for the recently proposed Goldstone-boson-exchange constituent quark model. Results for charge radii, magnetic moments, and electric as well as magnetic form factors are…
I give a brief overview of our current understanding of the internal partonic 3D structure of nucleons in momentum space. I discuss some recent extractions of transverse-momentum-dependent distributions for quarks, whose analyses in the…
Assuming the spin-independence for confining force, we give a covariant quark representation of general composite meson systems with definite Lorentz transformation properties. For benefit of this representation we are able to deduce…
The proton spin budget is discussed. Results are presented from inclusive and semi-inclusive deep inelastic scattering and from deeply virtual Compton scattering. They permit interpretations towards the determination of various…
The structure of the pion wave function in the relativistic constituent quark model is investigated in the explicitly covariant formulation of light-front dynamics. We calculate the two relativistic components of the pion wave function in a…
We generalize the Bartels-Ermolaev-Ryskin approach for the $g_1$ structure function at small-$x$ to determine the small-$x$ asymptotic behavior of the orbital angular momentum distributions in QCD. We present an exact analytical solution of…
We discuss the tremendous progress that has been towards an understanding of how the spin of the proton is distributed on its quark and gluon constituents. This is a problem that began in earnest twenty years ago with the discovery of the…
The spin and flavor fractions of constituent quarks in the proton are obtained from their chiral fluctuations involving Goldstone bosons. SU(3) flavor symmetry breaking suggested by the mass difference between the strange and up, down…
Assuming the spin-independence for confining force, we give a covariant quark representation of general composite meson systems with definite Lorentz transformation properties. For benefit of this representation we are able to deduce…
We present results on two-parton densities in coordinate space, which capture a fuller dynamical picture of the proton's internal structure, including information on the relative position between quarks and gluons in the transverse plane.…
Analyzing powers in inclusive pion production in high energy transversely polarized proton-proton collisions are studied theoretically in the framework of the quark recombination model. Calculations by assuming the SU(6) spin-flavor…
The proton spin puzzle has challenged our understanding of QCD for the last 20 years. We survey new developments in theory and experiment. The proton spin puzzle seems to be telling us about the interplay of valence quarks with chiral…