${{\boldsymbol \pi}^{0}}$ $\rightarrow$ ${{\boldsymbol \gamma}}$ positronium INSPIRE search

$\Gamma($ ${{\mathit \pi}^{0}}$ $\rightarrow$ ${{\mathit \gamma}}$ positronium$)/\Gamma($ ${{\mathit \pi}^{0}}$ $\rightarrow$ 2 ${{\mathit \gamma}}$ $)$
$\Gamma_{3}/\Gamma_{1}$
S009R12