Determination of the branching ratios $\hat{I}“(K_L\to 3\ddot{I}{€}^0)/\hat{I}“(K_L\to \ddot{I}{€}^{+}\ddot{I}{€}^{-}\ddot{I}{€}^0)$ and $\hat{I}“(K_L\to 3\ddot{I}{€}^0)/\hat{I}“(K_L\to \ddot{I}€e\hat{I}½)$

Abstract

Improved branching ratios were measured for the $K_L\to 3\ddot{I}{€}^0$ decay in a neutral beam at the CERN SPS with the NA31 detector: $\hat{I}“(K_L\to 3\ddot{I}{€}^0)/\hat{I}“(K_L\to \ddot{I}{€}^{+}\ddot{I}{€}^{-}\ddot{I}{€}^0)=1.611\pm 0.037$ and $\hat{I}“(K_L\to 3\ddot{I}{€}^0)/\hat{I}“(K_L\to \ddot{I}€e\hat{I}½)=0.545\pm 0.010$. From the first number an upper limit for $\hat{I}”I=5/2$ and $\hat{I}”I=7/2$ transitions in neutral kaon decay is derived. Using older results for the Ke3/K$\hat{I}¼$3 fraction, the 3$\ddot{I}{€}^0$ branching ratio is found to be $\hat{I}“(K_L\to 3\ddot{I}{€}^0)/\hat{I}{“}_{tot}=(0.211\pm 0.003)$, about a factor three more precise than from previous experiments.