Related papers: Polarized Structure Functions and the GDH Integral…
The $F_{2}$ structure functions of the inelastic lepton-hadron scattering is calculated in the case of non-zero intermediate gluon-quarks self-energy $M_{gq}^{2}$ and quasielastic limit. It is shown that in the quasielastic limit the…
A description of the generalized Gerasimov-Drell-Hearn sum rules for proton, neutron and deuteron is suggested. The proton consideration confirms the earlier conjecture, that the structure function $g_T$ features a smooth $Q^2-$dependence,…
Some simple relations between unpolarized and polarized quark parton distributions have direct experimental consequences which will be presented here. In particular, we will see that it is possible to relate the deep inelastic structure…
In order to obtain polarised parton densities we have made next to leading order QCD fit using experimental data on deep inelastic structure functions on nucleons. This fit is compared with the updated fit to coresponding spin asymmetries.…
The generalized Gerasimov-Drell-Hearn sum rule $I^{GDH}_{\gamma^*d}(Q^2)$ for deuteron electrodisintegration $d(e,e')np$ as function of the squared four-momentum transfer $Q^2$ is evaluated by explicit integration. The calculation is based…
We report on recent results on higher twist contributions to the unpolarized structure functions $F_2^{p,d}(x,Q^2)$ at N$^3$LO in the large $x$ region and constraints on the twist--3 contribution to polarized structure function…
In recent years, there has been a breakthrough in lattice calculations of $x$-dependent partonic distributions. This encompasses also distributions describing the 3D structure of the nucleon, such as generalized parton distributions (GPDs).…
Using iso-spin symmetry the quark-connected and disconnected contributions to the hadronic vacuum polarisation in a theory with N_f=2 flavours can be described as independent correlation functions, respectively. We show how this allows to…
We have initiated a programme to compute the lower moments of the unpolarised and polarised deep inelastic structure functions of the nucleon in the quenched approximation. We review our progress to date.
The polarized photon structure is described by two spin structure functions $g_1^\gamma$ and $g_2^\gamma$ which can be studied in the future polarized ep or e$^+$e$^-$ colliders. Here we investigate the QCD twist-3 effects in $g_2^\gamma$…
In the Framework of {\it{valon model}} we have calculated the parton distribution in a valon for both the polarized and unpolarized cases. These distributions are originated purely from the dressing of a valence quark in QCD and are common…
In the confinement regime at Q^2=0 the Gerasimov-Drell-Hearn (GDH) Sum Rule connects static properties of the nucleon with the difference of spin dependent doubly polarized total absorption cross sections of real photons. Now, for the first…
We explore the physics of the parton-hadron duality in the nucleon structure functions appearing in lepton-nucleon scattering. We stress that the duality allows one to extract the higher-twist matrix elements from data in the resonance…
We present the second order contributions to the coefficient functions for the parity violating polarized structure functions $g_L$ and $g_4$, thus completing the $\mathcal{O}(\alpha_S^2)$ knowledge on DIS structure functions. We obtain the…
Several new developments in the calculation and interpretation of hadron density-density correlation functions are presented. The asymptotic behavior of correlation functions is determined from a tree diagram path integral. A method is…
The twist--2 heavy flavor contributions to the polarized structure function $g_2(x,Q^2)$ are calculated. We show that this part of $g_2(x,Q^2)$ is related to the heavy flavor contribution to $g_1(x,Q^2)$ by the Wandzura--Wilczek relation to…
The virtual photon structure function $g_1^{\gamma}(x,Q^2,P^2)$, which can be obtained in polarized $e^{+}e^{-}$ colliding-beam experiments, is investigated for $\Lambda^2 \ll P^2 \ll Q^2$, where $-Q^2$ ($-P^2$) is the mass squared of the…
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 study polarized-spin structure functions of the nucleon within the bosonized Nambu-Jona-Lasinio model where the nucleon emerges as a chiral soliton. We present the electromagnetic polarized structure functions, $g_{1}(x)$ and $g_{2}(x)$…
The main features of the resonance structure of the nucleon are discussed, particular with regard to the helicity dependence of real and virtual photoabsorption. The dependence of the partial cross sections on both the resonance helicity…