SELECTED TOPICS ON RARE KAON PROCESSES IN THE STANDARD MODEL AND SUPERGRAVITY

Rare kaon processes appear to be particularly suitable to study the ex tensions of the standard model, especially if the possibility for even tual direct evidence becomes unlikely. In this review, we discuss proc esses that are important as a test of either the standard model or sup ergravity. Moreover, some of these are important even for both the sta ndard model and for supergravity. Particular attention is paid to the reduction of uncertainties in the calculation, especially the ones com ing from the confinement effects. Recent approaches, such as chiral pe rturbation theory, the large N(c)-expansion, QCD sum rules and lattice QCD, are discussed. This is found to be the best strategy in view of the fact that supersymmetric effects are rather tiny.