Isospin Breaking and Instantons in QCD Nucleon Sum Rules
High Energy Physics - Phenomenology
2014-11-17 v1 Nuclear Theory
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.
Keywords
Cite
@article{arxiv.hep-ph/9611311,
title = {Isospin Breaking and Instantons in QCD Nucleon Sum Rules},
author = {Hilmar Forkel and Marina Nielsen},
journal= {arXiv preprint arXiv:hep-ph/9611311},
year = {2014}
}
Comments
28 pages, REVTEX file and 5 Postscript figures