Related papers: Nucleon spin structure and its connections to vari…
Time and again, spin has been a key element in the exploration of fundamental physics. Spin-dependent observables have often revealed deficits in the assumed theoretical framework and have led to novel developments and concepts. Spin is…
We summarize three alternative extensions of the quark-valence picture of nucleon strangeness and spin, including (1) gluon spin in QCD, (2) Bjorken sum rule and QCD, (3) D--E meson mixing and tadpole leakage. All three approaches suggest…
Understanding the spin structure of the proton is one of the main challenges in hadronic physics. While the concepts of spin and orbital angular momentum are pretty clear in the context of non-relativistic quantum mechanics, the…
We investigate the relation between the topology of a nucleon and its spin composition. We approach this question in (1+1) dimensional single-flavor QCD with a large number of color. In this limit the theory can be shown to be dual to the…
C o n t e n t s 1. Introduction. 2. General Relations. 3. Small $x$ Domain -- Regge Behaviour. 4. The Parton Model. 5. Sum Rules in the Parton Model. 6. QCD Corrections to Sum Rules. 7. Nucleon Axial Coupling Constants. 8. The Experimental…
This talk presents recent calculations in full QCD of the lowest three moments of generalized parton distributions and the insight they provide into the behavior of nucleon electromagnetic form factors, the origin of the nucleon spin, and…
This article is a short introduction to the general topic of quantum spin systems. After a brief sketch of the history of the subject, the standard mathematical framework for formulating problems and results in quantum spin systems is…
The lowest three moments of generalized parton distributions are calculated in full QCD and provide new insight into the behavior of nucleon electromagnetic form factors, the origin of the nucleon spin, and the transverse structure of the…
Spin sum rules depend on the choice of a pivot, i.e. the point about which the angular momentun is defined, usually identified with the center of the nucleon. The latter is however not unique in a relativistic theory and has led to…
Dyson-Schwinger equation treatments of the strong interaction show that the presence and importance of nonpointlike diquark correlations within the nucleon are a natural consequence of dynamical chiral symmetry breaking. Using this…
In this short note the QED extension of the nucleon spin sum rule is considered. To this end, the leading-order (LO) QED evolution kernels for the quark/gluon helicity and orbital-angular-momentum (OAM) distributions are calculated, as well…
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…
Magic numbers lie at the heart of nuclear structure, reflecting enhanced stability in nuclei with closed shells. While the emergence of magic numbers beyond 20 is commonly attributed to strong spin-orbit coupling, the microscopic origin of…
We use the method of QCD sum rules in the presence of an external pion field to investigate isospin symmetry breakings in pion-nucleon couplings. Possible manifestations of such isospin symmetry breaking are examined in the context of…
A qualitative QCD analysis and a quantitative model calculation are given to show that the constituent quark model remains a good approximation even with the nucleon spin structure revealed in polarized deep inelastic scattering taking into…
The nucleon elastic form factors are of fundamental interest, provide a unique testing ground for QCD motivated models of nucleon structure and are of critical importance to our understanding of the electromagnetic properties of nuclei.…
Nucleon spin structure has been an active and exciting subject of interest for the last three decades. Recent precision spin-structure data from Jefferson Lab have significantly advanced our knowledge of nucleon structure in the valence…
We use a simple field theory model to investigate the role of the nucleon spin for the magnetic sum rules associated with the low-lying collective scissors mode in deformed nuclei. Various constraints from rotational symmetry are elucidated…
The problem of our understanding of the spin structure of the nucleon has been with us since the publication of the EMC measurements of the polarised structure function of the proton in 1987. In this talk a brief history of the subject is…
We present a simple explanation of the underlying physics in the use of hyperon decay data to obtain information about proton spin structure. We also present an alternative input using nucleon magnetic moment data and show that the results…