Instantons and Nucleon Magnetism

Abstract

We construct improved QCD sum rules for the nucleon magnetic moments by implementing direct-instanton contributions to the operator product expansion of the nucleon correlator in a magnetic background field. The instanton contributions are found to affect only those sum rules which had previously been considered unstable. The new sum rules show a high degree of stability and reproduce the experimental values of the nucleon magnetic moments for values of the magnetic quark condensate susceptibility which are consistent with other estimates.

arXiv comment10 pages, 2 figures. Invited talk given at "Hadron Physics 2000", Caraguatatuba, Sao Paulo, Brazil (April 10-15, 2000)