Introduction

The study of CP violation in neutral K decays has been, from the outset, the primary goal of a high-luminosity factory, like DANE. At the beginning, attention was focussed almost exclusively on the measurement of the direct CP-violation parameter, . Due to the very interesting work of Buchanan et al. [1], it has been realized that, in addition, a factory offers the unique possibility to make a clean test of the CPT symmetry, at the level of precision of few parts of CP-violating amplitudes, independently from possible conspiracies still allowed in presently measured quantities.

The aim of the present article is to provide a self-consistent introduction to the phenomenology of CP and CPT violation in neutral Kaon decays and to give a first illustration of the impact of DANE on the issue of the CPT symmetry.

More details are provided in the subsequent papers [2,3]. The calculation of in the Standard Theory is also reviewed here (but discussed in [3] in more detail). CP violation in charged Kaon decays is deferred to a later part of this Chapter [4].

Of course, there exist in the literature many excellent reviews of the subject, starting from the classical and influential article of Lee and Wu [5]. In the more recent literature, CPT symmetry in Kaon decays has been analyzed by Barmin et al. [6] and, with reference to the experiments at a factory, in Refs. [7,1].