Related papers: Exploring the proton spin structure

More than three decades has passed since the European Muon Collaboration published the first surprising result on the spin structure of the proton. Much theoretical and experimental progress has been made in understanding the origins of the…

Proton spin problem is given a new perspective with the proposition that spin is a topological invariant represented by a de Rham 3-period. The idea is developed generalizing Finkelstein-Rubinstein theory for Skyrmions/kinks to topological…

The paper focuses on considering some special precessional motions as the spin motions, separating the octonion angular momentum of a proton into six components, elucidating the proton angular momentum in the proton spin puzzle, especially…

Transverse single spin asymmetries can be a challenging tool in our understanding of the internal structure of hadrons. Some aspects and recent results are discussed.

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,…

I review recent developments in theoretical spin physics. Topics include pion production in nucleon-nucleon collisions, the implications of heavy quark spin symmetry for heavy hadron molecules, the nucleon electric dipole form factors and…

I discuss the present situation with regard to a variety of theoretical topics in hadronic spin physics: (a) global analysis of the g1 data---positivity at leading and next-to-leading order, renormalisation-scheme dependence,…

The twenty years since the announcement of the proton spin crisis by the European Muon Collaboration has seen tremendous progress in our knowledge of the distribution of spin within the proton. The problem is reviewed, beginning with the…

The leading order evolution of parton orbital angular momenta is treated in the probabilistic manner. As a result, the splitting probability matrix, while coinciding with the recent explicit calculations, is expressed in the terms of the…

The proton spin budget is discussed. Results are presented from inclusive and semi-inclusive deep inelastic scattering and from deeply virtual Compton scattering. They permit interpretations towards the determination of various…

The general question, crucial to an understanding of the internal structure of the nucleon, of how to split the total angular momentum of a photon or gluon into spin and orbital contributions is one of the most important and interesting…

Covariant version of the quark-parton model is studied. Dependence of the structure functions on the 3D quark intrinsic motion is discussed. The important role of the quark orbital momentum, which is a particular case of intrinsic motion,…

Using the equations of motion of QCD and Lorentz invariance relations, we show a new, more direct way of obtaining the decomposition of the proton's quark transverse angular momentum into its spin and orbital components. The new…

Physics perspectives are shown for future experiments in electron or positron scattering on nucleons, towards a deep and comprehensive understanding of the angular momentum structure of the nucleon in the context of Quantum Chromodynamics.…

I discuss two topics of current interest in the study of the spin structure of the nucleon. First, I discuss whether there is a sum rule for the components of the nucleon's angular moments. Second, I discuss the measurement of the nucleon's…

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…

The spin fractions and deep inelastic structure functions of the proton are analyzed using chiral field theory involving Goldstone bosons. A detailed comparison with recent chiral models sheds light on their successful description of the…

The notion of the spin is shown to have two constituents, as exemplified by the spin of the electron. The first one is related to the form of the wave equation and determines the fermion or boson particle type. This implies the spin taking…

The fact that the spins of the quarks in the proton, as measured in deep inelastic lepton scattering, only add up to about 30$\%$ of the spin of the proton is still not understood after 30 years. We show that our newly developed model for…

This is a review of recent developments in hadron structure within the framework of Lattice QCD. The main focus is on recent achievements in the evaluation of nucleon quantities, such as the axial charge, electromagnetic form factors, the…