Related papers: Spin structure function g_1 at low x: status and p…
We discuss perturbative evolution of the polarized structure function g_1 in the (x,Q^2) plane, with special regard to the small-x region. We determine g_1 in terms of polarized quark and gluon distributions using coefficient functions to…
I discuss a few interpolating sum rules for spin structure functions of the nucleon. Using the concept of duality, I argue that the $G_1$ sum rule, including the elastic contribution, is useful for learning higher twist matrix elements of…
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…
The structure function of the nucleus in the cumulative region $x>1$ is studied in terms of nucleon degrees of freedom. At high $Q^2$ the resulting expressions are presented as a sum of contributions from few-nucleon correlations.…
The spin structure functions g1 and g2 have been calculated in the resonance region and for small and intermediate momentum transfer. The calculation is based on a gauge-invariant and unitary model for one-pion photo- and electroproduction.…
We review the present status of polarized structure functions measured in deep-inelastic scattering. We discuss the x and Q^2 dependence of the structure function g_1, and how it can be used to test perturbative QCD at next-to-leading order…
The proton spin dependent structure function $g_1^p$ is analysed using the unified scheme incorporating both Altarelli-Parisi evolution and the double $ln^2(1/x)$ effects at low $x$. The latter are found to be very important in the region…
Deep inelastic structure functions for the nucleon are obtained in a constituent quark model on the light cone. Parton model formulas are derived. The negative slope of $F_{2}^{n}/F_{2}^{p} requires attraction between scalar quark pairs.…
The nucleon spin structure is studied at COMPASS via the measurement of the spin dependent properties of deep inelastic muon-deuteron scattering. Both inclusive and semi-inclusive observables are investigated, with the emphasis put on the…
We have measured the neutron structure function g$_{2}^{n}$ and the virtual photon-nucleon asymmetry A$_{2}^{n}$ over the kinematic range $0.014\leq x \leq 0.7$ and $1.0 \leq Q^{2} \leq 17.0$ by scattering 48.3 GeV longitudinally polarized…
It is shown that the quark-parton model in the standard infinite momentum approach overestimate the proton spin structure function $g_1(x)$ in comparison with the approach taking consistently into account the internal motion of quarks…
I discuss recent results from Jefferson Lab on the measurement of inclusive spin structure functions in the nucleon resonance region using polarized electron beams and polarized targets. Results on the first moment of the spin structure…
Recent progress from Jefferson Lab has significantly improved our understanding of the nucleon spin structure in the high-$x$ region. Results of a precision measurement of the neutron spin asymmetry, $A_1^n$, in the high-$x$ (valence quark)…
We present a comprehensive analysis of the nuclear effects important in DIS on polarized He-3 over a wide range of Bjorken x, 10^{-4} \leq x \leq 0.8. Effects relevant for the extraction of the neutron spin structure function, g1^n, from…
The explicit expressions for the non-singlet DIS structure function g_1 at small $x$ are obtained by resumming the leading logarithmic contributions. The role played by the fits for the initial parton densities currently used in the DGLAP…
We study the $Q^2$ variation of the first moment of the nucleon's spin-dependent structure function $G_1$. As $Q^2 \rightarrow 0$ the moment is determined by the low energy theorem for Compton scattering. In the deep-inelastic region the…
We have examined the spin structure of the proton in the region of the nucleon resonances (1.085 GeV < W < 1.910 GeV) at an average four momentum transfer of Q^2 = 1.3 GeV^2. Using the Jefferson Lab polarized electron beam, a spectrometer,…
Fundamental spin physics has made striking progresses in the last years; new ideas, experiments and data interpretations have been proposed and keep emerging. A review of some of the most important issues in the spin structure of nucleons…
The structure functions and low x working group summary of DIS06.
Understanding the nucleon spin structure in the regime where the strong interaction becomes truly strong poses a challenge to both experiment and theory. At energy scales below the nucleon mass of about 1 GeV, the intense interaction among…