New approach to $K^{0}-\bar{K^{0}}$ mixing

Abstract

A new QCD calculation of the B parameter of $K^{0}-\bar{K^{0}}$ mixing is presented. It makes use of polynomial kernels in dispersion integrals in order to practically eliminate the contributions of the unknown pseudoscalar strange continuum. This approach avoids the arbitrariness and instability inherent to the Borel exponential kernels used in previous sum rules calculations. A simultaneous calculation of the mixed quark gluon condensate $\langle g\bar{q}\sigma_{\mu\nu}\frac{\lambda^{a}}{2}\sigma_{\mu\nu}^{a}q\rangle$ which enters in the expression for B is presented. Finally the K-meson decay constant $f_{K}$ is calculated to five loop