Proton spin dynamics and axial singlet charge
TL;DR: In this paper, the authors consider the divergence of the gauge invariant flavour singlet axial current and show by a careful analysis that isospin-dependent terms persist in it and relate the axial singlet charge to the sum of the quark spin contributions and F D ratio.
About: This article is published in Physics Letters B.The article was published on 1991-10-03. It has received None citations till now. The article focuses on the topics: Proton spin crisis & Singlet state.
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TL;DR: In this article, the authors investigated the behavior under SU3×SU3 of the hadron energy density and the closely related question of how the divergences of the axial-vector currents and the strangeness-changing vector currents transform under SU 3×SU 3.
Abstract: We investigate the behavior under SU3×SU3 of the hadron energy density and the closely related question of how the divergences of the axial-vector currents and the strangeness-changing vector currents transform under SU3×SU3. We assume that two terms in the energy density break SU3×SU3 symmetry; under SU3 one transforms as a singlet, the other as the member of an octet. The simplest possible behavior of these terms under chiral transformations is proposed: They are assigned to a single (3,3*)+(3*,3) representation of SU3×SU3 and parity together with the current divergences. The commutators of charges and current divergences are derived in terms of a single constant c that describes the strength of the SU3-breaking term relative to the chiral symmetry-breaking term. The constant c is found not to be small, as suggested earlier, but instead close to the value (-sqrt[2]) corresponding to an SU2×SU2 symmetry, realized mainly by massless pions rather than parity doubling. Some applications of the proposed commutation relations are given, mainly to the pseudoscalar mesons, and other applications are indicated.
1,475 citations
University of Sheffield1, University of Warsaw2, Yale University3, CERN4, University of Liverpool5, Lancaster University6, University of Oxford7, Laboratoire d'Annecy-le-Vieux de physique des particules8, RWTH Aachen University9, University of Freiburg10, University of Turin11, Uppsala University12, Max Planck Society13
TL;DR: An investigation of the spin structure of the proton in deep inelastic scattering of polarised muons on polarised protons was performed in this article, where the spin was investigated in the context of the deep scattering process of polarized muons.
813 citations
TL;DR: In this paper, it was shown that the anomalous (gluonic) U (1) A current, K μ, is not in general to be identified with the gluon spin.
579 citations
CERN1
TL;DR: In this article, it was shown that the first moment of the polarized proton structure function is not suppressed by a power of the strong coupling evaluated at a large scale, which is consistent with a large quark spin component.
433 citations
TL;DR: In this paper, it was shown that the forward matrix elements of the flavor singlet axial vector current do not measure the helicity carried by quarks and anti-quarks but also include a spin-dependent gluonic component due to the anomaly.
338 citations