Related papers: Gluon Contribution to the Transverse Spin Structur…
We study the covariant version of the quark-parton model, in which the general rules of the angular momentum composition are accurately taken into account. We demonstrate how these rules affect the relativistic interplay between the quark…
The gluon distribution is obtained from the Golec-Biernat-W$\ddot{\mathrm{u}}$sthoff (GBW) and Bartels, Golec-Biernat and Kowalski (BGK) models at low $x$. We derive analytical results for the unintegrated color dipole gluon distribution…
Effect of the quark intrinsic motion on the proton spin structure functions is demonstrated. It is shown, that the covariant version of the quark-parton model taking into account the orbital motion gives the consistent picture of the proton…
We have measured the spin structure functions $g_1$ and $g_2$ of $^3$He in a double-spin experiment by inclusively scattering polarized electrons at energies ranging from 0.862 to 5.07 GeV off a polarized $^3$He target at a 15.5$^{\circ}$…
The explicit expressions describing the structure function g_1 at arbitrary x and Q^2 are obtained. In the first place, they combine the well-known DGLAP expressions for g_1 with the total resummation of leading logarithms of x, which makes…
In this letter we suggest the generalization of $k_T$-factorization formula for inclusive gluon production for the dense-dense parton system scattering. It turnes out that the soft gluon production with transverse momentum $p_T$ is…
Using lattice QCD, we calculate the twist-2 contribution $a_2$ to the third Mellin moment of the spin structure functions $g_1$ and $g_2$ in the nucleon. In addition we evaluate the twist-3 contribution $d_2$. Our computations make use of…
The spin structure of the nucleon is analyzed in the framework of a Lorentz-invariant formulation of baryon chiral perturbation theory. The structure functions of doubly virtual Compton scattering are calculated to one-loop accuracy (fourth…
We calculate the spin dependent structure functions g1(x) and g2(x) of the proton and neutron. Our calculation uses the meson cloud model of nucleon structure and includes the effects of kinematic terms which mix transverse and longitudinal…
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 present the calculation of the leading instanton contribution to the scaling dimensions of twist-two operators with arbitrary spin and to their structure constants in the OPE of two half-BPS operators in $\mathcal N=4$ SYM. For spin-two…
We have extracted QCD matrix elements from our data on double polarized inelastic scattering of electrons on nuclei. We find the higher twist matrix element \tilde{d_2}, which arises strictly from quark- gluon interactions, to be…
The nucleon mass corrections are calculated to all polarized structure functions for neutral and charged current deep inelastic scattering in lowest order in the coupling constant. The impact of the target mass corrections on the general…
The positivity bound for the transverse asymmetry $A_2$ may be improved and applied for each quark flavor separately. We use it to test the consistency of twist-two approximation for the transverse spin-dependent ($g_T$) and the…
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…
Renormalisation induces anomalous contributions in light-cone correlation functions. We discuss the role of the axial anomaly and gluon topology in non-forward parton distributions noting that non-forward matrix elements of the gluonic…
We present a first study of gluonic twist-four corrections to the deep inelastic structure function F_2 at small x and small Q^2. The calculations are based upon the double logarithmic approximation of the coupled twist-four evolution…
We present a detailed analysis of resonance contributions in the context of higher twist effects in the moments of the proton spin structure function g_1. For each of these moments, it is found that there exists a characteristic Q^2 region…
The nonperturbative $Q^2$- dependence of the sum rules for the structure functions of polarized $e(\mu)N$ scattering is discussed. The determination of twist-4 corrections to the structure functions at high $Q^2$ by QCD sum rules is…
Perturbation theory in the nonperturbative QCD vacuum and the non-Abelian Stokes theorem, representing a Wilson loop in the SU(2) gluodynamics as an integral over all the orientations in colour space, are applied to derivation of the…