Determination of the branching ratios $\Gamma (K_L \to 3 \pi^0) / \Gamma (K_L \to \pi^+ \pi^- \pi^0)$ and $\Gamma (K_L \to 3 \pi^0) / \Gamma (K_L \to \pi e \nu )$

TL;DR

This paper reports precise measurements of the branching ratios for specific neutral kaon decays, providing insights into isospin transitions and improving the accuracy of the $K_L o 3 \pi^0$ decay rate.

Contribution

The study presents improved measurements of key kaon decay branching ratios, refining previous results and enabling better understanding of isospin transitions in neutral kaon decays.

Findings

Measured branching ratios with higher precision.

Derived upper limits for certain isospin transitions.

Refined the total $K_L o 3 \pi^0$ decay rate.

Abstract

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