Flavor eigenstate
= Flavor eigenstate
A <flavor eigenstate> is a state with a definite flavor label in the specified interaction or flavor-charge basis. For neutral <kaons>, $K^0=d\bar s$ and $\bar K^0=s\bar d$ have definite opposite <strangeness>. <Weak interactions> mix them, so these flavor states are not the <mass eigenstates>. The precise flavor basis must be specified when discussing mixing.