It turns out that although the K L and K S are weak eigenstates (because they have definite lifetimes for decay by way of the weak force), they are not quite CP eigenstates.
Selgitati, et isegi arvestades sellega, et KL ja KS on iseenda nõrgad olekud (sest nad omavad kindlat eluiga lagunemises nõrga vastasmõju raames), ei ole nad täielikult CP-olekud.