Lellouch-Lüscher factor for the $K\to 3\pi$ decays

Jin-Yi Pang, Rishabh Bubna, Fabian Müller +2

We derive an explicit expression for the Lellouch-Lüscher (LL) factor in the $K\to 3\pi$ decays at leading order (without derivative couplings). Several important technical details a…