THE PERTURBATIVE αs CORRECTIONS TO THE $K^0 - \bar K^0 $ MIXING MATRIX ELEMENT

Abstract

The leading αs corrections to the B parameter of the [Formula: see text] mixing matrix element are calculated within the sum rules method. Numerical estimates given in the framework of the factorization hypothesis for vacuum expectation values of four-quark local operators show a decrease of the [Formula: see text] matrix element from the factorized value by about 20% at the normalization point μ~1 GeV. The nonanalytical dependence of the B parameter on the kaon mass mK (~a, log mK) is discovered in the chiral limit.