Vacuum Saturation Hypothesis and QCD Sum Rules

Abstract

The accuracy of the vacuum saturation hypothesis is discussed using the examples of vacuum expectation values of four-quark operators and the parameter $B$, which determines the short-distance contribution to the $K^0-{\bar{K}}^0$ mixing. Note added: The approach based on sum rules in position (x-)space as elaborated in the paper is relevant and useful tool for the current phenomenology. In particular, it provides the unique possibility of direct non-perturbative estimation of the VEV's of four-quark operators renormalized in any scheme, including the MSbar one.

Comments: submitted to make it easier accessible for an interested reader