Related papers: Unitarity and nonperturbative effects in the spin …
We show that the nonlinear corrections to the longitudinal structure function can be tamed the singularity behavior at low x values, with respect to GLR-MQ equations. This approach can determined the shadowing longitudinal structure…
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…
We present a quantum theory for one-dimensional spin-1/2 multiferroics, where the vector spin chirality couples with the electric polarization. Based on exact diagonalization and bosonization, it is shown that quantum fluctuations…
Chiral constituent quark model with configuration mixing (\chiCQM_{{\rm config}}) is known to provide a satisfactory explanation of the ``proton spin problem'' and related issues. In order to enlarge the scope of \chiCQM_{{\rm config}}, we…
We discuss noncollinear magnetic phenomena whose local order parameter is characterized by more than one spin vector. By focusing on the simple cases of 2D triangular and 3D pyrochlore lattices, we demonstrate that their low-energy theories…
The Chiral Perturbation Theory (ChPT) has been very successful in describing low-energy hadronic properties in the non-perturbative regime of Quantum Chromodynamics. The results of ChPT, many of which are currently under active experimental…
Spin polarizabilities of the nucleon are discussed in the framework of fixed-t and backward-angle dispersion relations, chiral perturbation theory, and the non-relativistic quark model. Calculations with the dispersion relations generally…
We investigate the relations between the spin structure functions in the scaling and resonance regions. We examine the possible duality between the two, and draw inferences for the behavior of the asymmetry A_1 at large x. Finally, we point…
At large N_c the nucleon can be viewed as a soliton of the effective chiral lagrangian. This picture of nucleons allows a consistent nonperturbative calculation of the leading-twist parton distributions at a low normalization point. We…
We compute the lower moments of the structure functions of $\pi$ and $\rho$. Of particular interest are the spin-dependent structure functions of the $\rho$ as they give new information about quark binding effects.
New experimental results on the spin dependent structure functions g_1 and g_2 which are determined from deep-inelastic scattering experiments at CERN, SLAC and DESY are reported. These results are used to evaluate the Bjorken sum rule and…
Unitarization schemes can be reduced to non-linear equations which saturate at small $b$ the evolution of the elastic amplitude with $s$, and which mimic parton saturation in the non-perturbative regime. These equations enable us to study…
Inclusive and diffractive structure functions for electron-proton scattering are calculated in a semiclassical approach at large momentum transfer $Q^2$ and small values of the scaling variable $x$. The basic process is the production of a…
We present an update of an on-going project to determine the disconnected contributions to hadronic structure, specifically, the scalar matrix element and the quark contribution to the spin of the nucleon.
We present a measurement of the deuteron spin-dependent structure function g1d based on the data collected by the COMPASS experiment at CERN during the years 2002-2004. The data provide an accurate evaluation for Gamma_1^d, the first moment…
Several examples for the role of orbital angular momentum and spin-orbit correlations in hadron structure are discussed.
Chirality-induced spin selectivity has been reported in many experiments, but a generally accepted theoretical explanation has not yet been proposed. Here, we introduce a simple model system of a straight cylindrical free-electron wire,…
The spin-dependent structure functions $g_1(x)$, $g_2(x)$, ${g}_2^{WW}(x)$ and ${\bar g}_2(x)$ and their moments are studied in the CM bag model. The results show that (i) $\int_0^1g_2(x)dx=0$, i.e. the Burkhardt-Cottingham sum rule holds,…
The theoretical predictions of the chiral quark soliton model for the unpolarized and longitudinally polarized structure functions of the nucleon are compared with recent high energy data. The theory is shown to explain all the…
A previous approach with Fermi-Dirac distributions for fermion partons is here improved to comply with the expected low $x$ behaviour of structure functions. We are so able to get a fair description of the unpolarized and polarized…