Kaon CP eigenstates
= Kaon CP eigenstates
{title2=$CP|K_{1,2}\rangle=\pm|K_{1,2}\rangle$}
The <CP eigenstates> of neutral <kaons> depend on a flavor-state phase convention. Using $CP|K^0\rangle=-|\bar K^0\rangle$, set $|K_1\rangle=(|K^0\rangle-|\bar K^0\rangle)/\sqrt2$ and $|K_2\rangle=(|K^0\rangle+|\bar K^0\rangle)/\sqrt2$. They are respectively <CP> even and odd. Reversing the flavor-exchange sign reverses which written sum is even; it does not change the <CP> eigenvalues. With <CP violation>, the physical short- and long-lived states need not equal these <CP eigenstates>; <kaon CP mixing parameter> and <neutral-kaon CP impurity and two-pion decay> describe the mixtures.