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arXiv · hep-ph/9611311

Isospin Breaking and Instantons in QCD Nucleon Sum Rules

Hilmar Forkel·Marina Nielsen
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Abstract

We study isospin breaking instanton corrections to the operator product expansion of the nucleon correlation functions. After a comparison with quark model calculations based on the 't Hooft interaction, we examine the role of instantons in the corresponding QCD sum rules. Instanton contributions are found to be absent in the chirally even sum rule, but significant in the chirally-odd one. They improve the consistency of both sum rules and favor a value of the isovector quark condensate close to the chiral estimate.

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Hilmar Forkel, Marina Nielsen. 1996-11-12. Isospin Breaking and Instantons in QCD Nucleon Sum Rules. https://doi.org/10.1103/physrevd.55.1471

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