Isospin Breaking in $K\to 3\pi$ Decays I: Strong Isospin Breaking

Abstract

The CP conserving amplitudes for the decays $K\to 3\pi$ are calculated in Chiral Perturbation Theory. The calculation is made at the next-to-leading order including strong and local electromagnetic isospin breaking. A comparison is made between the squared amplitudes with and without isospin violation to estimate the size of the effect. We find corrections of order five percent in the amplitudes.

Comments: 25 pages, 7 figures