Spin-dependent twist-4 matrix elements from the instanton vacuum: Flavor-singlet and nonsinglet

Abstract

We estimate the twist-4 spin-1 nucleon matrix element f_2 in an instanton-based description of the QCD vacuum. In addition to the flavor-nonsinglet we compute also the flavor-singlet matrix element, which appears in next-to-leading order of the (1/N_c)-expansion. The corresponding twist-3 spin-2 matrix elements d_2 are suppressed in the packing fraction of the instanton medium, (\bar ρ)/(\bar R) << 1. We use our results to estimate the leading (1/Q^2) power corrections to the first moment of the proton and neutron spin structure functions G_1, as well as the intrinsic charm contribution to the nucleon spin.

arXiv comment17 pages, 4 eps figures included

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Cited by in corpus (24)

• The QCD Running Coupling
• The Spin Structure of the Nucleon
• Experimental determination of the evolution of the Bjorken integral at low Q^2
• Experimental study of isovector spin sum rules
• High precision determination of the $Q^2$-evolution of the Bjorken Sum
• QCD Running Couplings and Effective Charges
• Measurement of Dijet Production at Low Q^2 at HERA
• Nucleon gravitational form factors from instantons: forces between quark and gluon subsystems
• Determination of the Proton Spin Structure Functions for 0.05 < Q^2 < 5 GeV^2 using CLAS
• The Gerasimov-Drell-Hearn Sum Rule and the Spin Structure of the Nucleon
• Measurements of $d_2^n$ and $A_1^n$: Probing the neutron spin structure
• Sum Rules and Moments of the Nucleon Spin Structure Functions
• On the Role of Higher Twist in Polarized Deep Inelastic Scattering
• QCD radiative and power corrections and Generalized GDH sum rules
• A Precision Measurement of the Neutron Twist-3 Matrix Element $d_2^n$: Probing Color Forces
• Higher twist analysis of the proton g_1 structure function
• Higher moments of nucleon spin structure functions in heavy baryon chiral perturbation theory and in a resonance model
• Higher twists in polarized DIS and the size of the constituent quark
• Nucleon electric dipole moment from polarized deep inelastic scattering
• A novel determination of non-perturbative contributions to Bjorken sum rule
• Instanton-Induced Correlations in Hadrons
• Target mass corrections to matrix elements in nucleon spin structure functions
• Modeling power corrections to the Bjorken sum rule for the neutrino structure function F_1
• Nucleon matrix element of Weinberg's CP-odd gluon operator from the instanton vacuum