Octet Spin Fractions and the Proton Spin Problem

Abstract

The relatively small fraction of the spin of the proton carried by its quarks presents a major challenge to our understanding of the strong interaction. Traditional efforts to explore this problem have involved new and imaginative experiments and QCD based studies of the nucleon. We propose a new approach to the problem which exploits recent advances in lattice QCD. In particular, we extract values for the spin carried by the quarks in other members of the baryon octet in order to see whether the suppression observed for the proton is a general property or depends significantly on the baryon structure. We compare these results with the values for the spin fractions calculated within a model that includes the effects of confinement, relativity, gluon exchange currents and the meson cloud required by chiral symmetry, finding a very satisfactory level of agreement given the precision currently attainable.

5 pages, 3 figures

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Cited by in corpus (12)

• Improved Treatment of Dark Matter Capture in Neutron Stars III: Nucleon and Exotic Targets
• A Feynman-Hellmann approach to the spin structure of hadrons
• Light-quark contributions to the magnetic form factor of the Lambda(1405)
• Axial form factors of the octet baryons in a covariant quark model
• SU(3)-flavour breaking in octet baryon masses and axial couplings
• Axial-vector form factors for the low lying octet baryons in the chiral quark constituent model
• $N^{\ast }$ Form Factors based on a Covariant Quark Model
• Holographic estimate of the meson cloud contribution to nucleon axial form factor
• Properties of JP = 1/2+ baryon octets at low energy
• Singlet baryons in the graded symmetry approach to partially quenched QCD
• The quark orbital angular momentum of ground state octet baryons
• Progress in resolving charge symmetry violation in nucleon structure