CPviolation inK→3π

For the weak nonleptonic decay K→3π, we analyze the amount of CP violation expected to arise in the Kobayashi-Maskawa model using two recently uncovered aspects: (1) quadratic terms in the K→3π amplitude (found in the CP-conserving data) and (2) electromagnetic and isospin-breaking effects in the relation of the CP-violating parameters of K→2π and K→3π. Previous to the inclusion of these effects the non-ε signal in ${\eta }_{+\mathrm{-}0}$ (${\eta }_{+\mathrm{-}0}$=ε+${\epsilon }_{+\mathrm{-}0}^{\mathcal{’}}$) required interference with the highly suppressed ΔI=(3/2 amplitude; however in the present analysis the ${\epsilon }_{+\mathrm{-}0}^{\mathcal{’}}$ signal is not suppressed. We estimate values for ${\epsilon }_{+\mathrm{-}0}^{\mathcal{’}}$ about an order of magnitude larger than previously anticipated, although still smaller than ε.