Short-Distance Effects in the K⁰-K̄⁰ Mixing in the Standard Model

Abstract

From the accelerator experiments in the 1950s up to the CP experiments of the present time the neutral kaon complex has remained one of the most interesting systems in nature. The breakthroughs which it has provided in our knowledge of fundamental physics have been crucial in establishing the standard SU(3)×SU(2)×U(l) model (SM) of electroweak and strong interactions. More recently there have been claims that the existing CP-violation measurements represent a serious threat to the standard model. In this paper I would like to illustrate that such announcements are premature in view of the degree of accuracy in theoretical predictions. Therefore, I would stick to the theoretically more tractable short-distance contributions and then I shall gradually show that, on the one hand, their present treatment is incomplete and, on the other hand, they have to be supplemented at various stages (which I intend to explicate) by some sort of long-distance (LD) calculation.