Neutral Decay Branching Ratios of theη0Meson

The branching ratios for the decay of the ${\eta }^0$ meson into $3{\pi }^0$, ${\pi }^0\gamma \gamma$, and $\gamma \gamma$ have been measured. Under the assumption that no other neutral decays are significant, the results are $\frac{({\eta }^0\to 3{\pi }^0)}{({\eta }^0\to \gamma \gamma )}=0.88\mathrm{}\pm 0.16$ and $\frac{({\eta }^0\to {\pi }^0\gamma \gamma )}{({\eta }^0\to \gamma \gamma )}<~0.28$ (95% confidence-level upper limit).