QCD Calculation of $K^0 - \bar K^0$ mixing from three-point function sum rules

We calculate theB parameter for $K^0 - \bar K^0$mixing in the framework of QCD sum rules for a three-point function involving pseudoscalar currents, and contrast our results with other calculations. We findB=0.5±0.1±0.2, where the first error reflects uncertainties in the various QCD parameters and the second one is an estimate of uncalculated three-loop radiative and higher order quark mass corrections