Neutral B meson mixing
= Neutral B meson mixing
{title2=$B^0\leftrightarrow\bar B^0$}
Weak box diagrams change neutral bottom-meson <quark flavor>[flavour]. The propagating eigenstates are combinations $p|B^0\rangle\pm q|\bar B^0\rangle$. For a shared final state, interference is governed by $\lambda_f=(q/p)(\bar A_f/A_f)$; in the dominant charmonium-kaon mode this yields the CKM angle through $\lambda_f\simeq-e^{-2i\beta}$, with stated meson and kaon phase conventions.