Quark off-shell contributions to $K_L\to \gamma \gamma$ in a bound-state approach

D. Kekez, D. Klabucar, K. Kumericki +1

We present a new piece of evidence in favour of the importance of the quark off-shellness in the kaon. The matrix elements of the flavour-changing operators for $K_L\to \gamma \gamma$ comply…