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.

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