Theoretical Estimate(s) of the CP-Violating Quantity ɛ′/ɛ in K → 2π decays

Abstract

Abstract.I give a short presentation of the theoretical prediction of ε ′ /ε. Short distance and especially long distance aspects of the computation is discussed. I consentrate on the general framework and the chiral quark model approach, while other approaches are also shortly presented. Because of the intrinsic uncertainties of the long-distance computations, it is unlikely that new physics effects can be disentangled from the standard model prediction.