Related papers: Calculations of Higher Twist Distribution Function…
We explore the possibility to construct higher-twist parton distributions in a nucleon at some low reference scale from convolution integrals of the light-cone wave functions (WFs). To this end we introduce simple models for the…
Deep inelastic polarized and unpolarized structure functions for a free nucleon are obtained in a modified Center-of-Mass bag model, which includes the symmetry breaking effects from spin-dependent interactions. The quark distribution…
We start from an MIT-bag model calculation which provides information about the constituent quark distributions in the nucleon. The constituent quarks, however, are themselves considered as complex objects whose partonic substructure is…
We review the nucleon's twist-3 polarized structure functions from the viewpoint of gauge invariant, nonlocal light-cone operators in QCD. We discuss a systematic treatment of the polarized structure functions and the corresponding parton…
The quark-parton model calculation including the effects of intrinsic transverse momentum and of all six twist-two distribution functions of quarks in polarized nucleons is performed. It is demonstrated that new twist-two quark distribution…
We calculate the chiral odd quark distributions and the corresponding structure functions $h_T(x,Q^2)$ and $h_L(x,Q^2)$ within the Nambu-Jona-Lasinio chiral soliton model for the nucleon. The $Q^2$ evolution of the twist-2 contributions is…
We define twist-two and twist-three quark fragmentation functions in Quantum Chromodynamics (QCD) and study their physical implications. Using this formalism we show how the nucleon's transversity distribution can be measured in single pion…
We report on the results of a recent work, where we explore the possibility to construct higher-twist parton distributions in a nucleon at some low reference scale from convolution integrals of the light-cone wave functions (LCWFs). These…
The Sivers function, an asymmetric transverse-momentum distribution of the quarks in a transversely polarized nucleon, is calculated in the MIT bag model. The bag quark wave functions contain both $S$-wave and $P$-wave components, and their…
We study the Q^2 evolution of the nucleon's chiral-odd twist-3 distribution h_L(x,Q^2) starting from the MIT bag model calculation. A simple GLAP equation for h_L(x,Q^2) obtained at large N_c is used for the Q^2 evolution. The correction…
Nuclear parton distributions and structure functions are determined in an effective chiral quark theory. We also discuss an extension of our model to fragmentation functions.
At the low energy, {\sl hadronic}, scale we calculate Orbital Angular Momentum (OAM) twist-two parton distributions for the relativistic MIT bag model and for non-relativistic quark models. We reach the scale of the data by leading order…
We present for the first time the complete twist-4 result for the semi-inclusive deeply inelastic scattering $e^- N \to e^-qX$ with polarized electron and proton beams at the tree level of pQCD. The calculations have been carried out using…
We study the QCD evolution for the twist-three quark-gluon correlation functions associated with the transverse momentum odd quark distributions. Different from that for the leading twist quark distributions, these evolution equations…
Hadron spin physics is now one of the most active fields of physics. Especially in the last ten years, great progress has been made both theoretically and experimentally that has considerably improved our knowledge of the spin structure of…
We compute the full x - dependence of the proton and neutron spin structure functions in the MIT bag model, including the effect of gluon exchange and the meson cloud. Impressive agreement is found for x larger than 0.1, where polarised…
The nucleon structure functions are studied with a special emphasis on diquark correlations inside the nucleon. Assuming a phenomenological diquark-quark model of the nucleon at the low energy hadronic scale, we calculate the leading twist…
Higher twist effects in the deeply inelastic scattering are studied. We start with a short review of the theoretical results on higher twists in QCD. Within the saturation model we perform a twist analysis of the nucleon structure functions…
In order to study twist-3 and transverse momentum dependent parton distributions, we use light-front time-ordered pQCD at order $\alpha_s$ to calculate various distribution functions for a dressed quark target. This study enables us to…
We investigate one-particle semi-inclusive processes in lepton-hadron scattering. In unpolarized scattering order $Q^{-1}$ corrections appear only when transverse momenta are detected. We consider the twist two and three matrix elements and…