Search forKS→π+π−π0

Abstract

A search for $K_S$ decaying into the final state ${\pi }^{+}{\pi }^{-}{\pi }^0$ has been made by studying the time distribution of $3\pi$ decays of neutral $K$ mesons produced in the reaction $K^{+}d\to K^0\mathrm{pp}$. On the basis of 99 $3\pi$ events, we find for the complex parameter $x+iy$, the ratio of the amplitude $K_s\to 3\pi$ to the amplitude $K_L\to 3\pi$, $x=0.47\mathrm{}\pm 0.20$, $y=-0.10_{-0.32\mathrm{}}^{}{}_{}{}^{+0.37\mathrm{}}$. Our result is consistent with no $K_S$ decays into ${\pi }^{+}{\pi }^{-}{\pi }^0$ and no $\mathrm{CP}$ violation. Assuming $x=y=0\mathrm{}$, we obtain ${\Gamma }_L\left(3\mathrm{}\pi \right)=(2.71\mathrm{}\pm 0.28)\times {10}^6$ ${\sec }^{-1\mathrm{}}$.