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We compute the nucleon matrix elements of QCD operators of twist 3 and 4 in the instanton vacuum. We consider the operators determining 1/Q 2 –power corrections to the Bjorken, Ellis–Jaffe and Gross–Llewellyn-Smith sum rules. The nucleon is described as a soliton of the effective chiral theory derived from instantons in the 1/N c –expansion. QCD operators(More)
We study the off-forward quark distributions (OFQD's) in the chiral quark-soliton model of the nucleon. This model is based on the large-N c picture of the nucleon as a soliton of the effective chiral lagrangian and allows to calculate the leading twist quark– and antiquark distributions at a low normalization point. We demonstrate the consistency of the(More)
  • D I Diakonov, M V Polyakov, C Weiss
  • 1996
We propose a method to evaluate hadronic matrix elements of QCD gluon operators in the instanton vacuum. We construct the ground state of the interacting instanton ensemble for non-zero ϑ–angle using a variational principle. A method to study the ϑ–dependence of observables on the lattice is suggested. We then derive the effective fermion action, which(More)
We study the non-forward matrix elements of twist–2 QCD light–ray operators and their representations in terms of skewed and double distributions, considering the pion as well as the nucleon. We point out the importance of explicitly including all twist–2 structures in the double distribution representation, which naturally leads to a " two–component "(More)
The 1/N c –expansion of QCD suggests large flavor asymmetries of the polarized antiquark distributions in the nucleon. This is confirmed by model calculations in the large–N c limit (chiral quark–soliton model), which give sizable results for ∆¯ u(x)− ∆ ¯ d(x) and ∆¯ u(x)+ ∆ ¯ d(x)− 2∆¯ s(x). We compute the contributions of these flavor asymmetries to the(More)
We compute in the instanton vacuum the nucleon matrix elements of the twist–4 QCD operators describing power corrections to the second moments of the unpolar-ized structure functions, F L and F 2. Our approach takes into account the leading contribution in the packing fraction of the instanton medium, ¯ ρ/ ¯ R ≪ 1. Paramet-rically leading are the matrix(More)
We summarize recent developments in understanding the concept of generalized parton distributions (GPDs), its relation to nucleon structure, and its application to high–Q 2 electropro-duction processes. Following a brief review of QCD factorization and transverse nucleon structure , we discuss (a) new theoretical methods for the analysis of deeply–virtual(More)
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(More)