Related papers: Quark Orbital-Angular-Momentum Distribution in the…
We calculate the leading-twist helicity-dependent generalized parton distributions (GPDs) of the proton at finite skewness in the Nambu--Jona-Lasinio (NJL) model of quantum chromodynamics (QCD). From these (and previously calculated…
We introduce the spin-operator representation for the gluon as well as quark distribution functions as nucleon matrix element of the gauge-invariant bilocal light-cone operators in QCD. To identify the relevant spin operators for quarks and…
Longitudinal and transverse parton distributions for pion and nucleon are calculated from hadron vertexes obtained by a study of form factors within relativistic quark models. The relevance of the one-gluon-exchange dominance at short range…
We propose a unified new approach to describe polarized and unpolarized quark distributions in the proton based on the gauge-gravity correspondence, light-front holography, and the generalized Veneziano model. We find that the…
We investigate the Wigner distributions of $\bar{u}$ and $\bar{d}$ quarks in a proton using the overlap representation within the light cone formalism. Using the light cone wave functions which are obtained from the baryon-meson fluctuation…
Applying the connection between the parton Wigner distribution and orbital angular momentum (OAM), we investigate the probe of the gluon OAM in hard scattering processes at the planned electron-ion collider. We show that the single…
In a nonstandard way we split up the polarized quark distributions $g_T$ and $h_L$ into their twist-two, quark-mass, and interaction-dependent parts, emphasizing the sensitivity to quark intrinsic transverse momentum. We show how to derive…
We derive a nonperturbative transverse momentum distribution for partons using a potential model to describe the quark-quark interaction inside the proton. We use this distribution to calculate the diferential cross-section of…
We review the status of our understanding of nucleon structure based on the modelling of different kinds of parton distributions. We use the concept of generalized transverse momentum dependent parton distributions and Wigner distributions,…
Fourier transforms of GPDs describe the distribution of partons in the transverse plane. The 2nd moment of GPDs has been identified by X.Ji with the angular momentum (orbital plus spin) carried by the quarks - a fundamental result that is…
We discuss the general formalism for the calculation in light-front quark models of the fully unintegrated, off-diagonal quark-quark correlator of the nucleon, parametrized in terms of generalized transverse momentum dependent parton…
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…
The alternative to the standard formulation of the quark-parton model is proposed. Our relativistically covariant approach is based on the solution of the master equations relating the structure and distribution functions, which…
The gauge invariant definition of the spin dependent gluon distribution function from first principle is necessary to study the proton spin crisis at high energy colliders. In this paper we derive the gauge invariant Noether's theorem in…
Several possibilities to relate the $t$-dependence of Generalized Parton Distributions (GPDs) to the distribution of angular momentum in the transverse plane are discussed. Using a simple spectator model we demonstrate that non of them…
We investigate the quark angular momentum in a model with the nucleon being a quark and a spectator. Both scalar and axial-vector spectators are included. We perform the calculations in the light-cone formalism where the parton concept is…
In this contribution I discuss transverse momentum dependent quark distributions and their operator structure. Some of the experimental signatures, in particular in Drell-Yan scattering, are given.
We compare the orbital angular momentum of the 'quark' in the scalar diquark model as well as that of the electron in QED (to order {\alpha}) obtained from the Jaffe-Manohar de- composition to that obtained from the Ji relation. We estimate…
The data from the last seven experiments performed on polarized deep--inelastic scattering on proton and neutron (or deuteron) targets have been analyzed in search of a precise determination of the spin fraction carried by the quarks in the…
We present a first calculation of the heavy flavor contribution to the longitudinally polarized deep-inelastic scattering structure function $g_1^{Q}$, differential in the transverse momentum or the rapidity of the observed heavy quark $Q$…