Meson Cloud, QCD Nucleon Correlator and Chiral Perturbation Theory

We introduce a model for nucleons with correlators that include the propagation of pseudo Goldstone bosons as well as the standard correlators for nucleons used in QCD sum rules. From the comparison with experimental nucleon magnetic dipole moments we estimate the probability of a pion cloud in a nucleon. The masses obtained from the sum rules are almost independent of the cloud contributions. We show that the model is consistent with chiral perturbation theory, and solves a long-standing problem on obtaining the leading non-analytic correction to the nucleon mass in QCD sum rules.