Three-Pion States in theKL→μ+μ−Puzzle

Abstract

Contributions to the absorptive $K_L\to 2\mu$ amplitude coming from intermediate $3\pi$ states are estimated on the basis of recent soft-pion results for the process $3\pi \to 2\gamma$. These contributions turn out to be far too small, by 4 orders of magnitude, to resolve the $K_L\to 2\mu$ puzzle.