On the orthogonality of K⁰-meson nonleptonic weak-decay residues

Using nonperturbative techniques, we show that interference terms due to the failure of the exact semi-group behaviour of the nonleptonic weak-decay law may be O(α³), where α² ∼ 10⁻³, independently of the size of the weak-coupling constant. Consequences of these interference terms for regeneration experiments are calculated.