  BESIII data show a particular angular distribution for the decay of the
$J/\psi$ and $\psi(2S)$ mesons into the hyperons $\Lambda\overline{\Lambda}$
and $\Sigma^0\overline{\Sigma}^0$. More in details the angular distribution of
the decay $\psi(2S) \to \Sigma^0\overline{\Sigma}^0$ exhibits an opposite trend
with respect to that of the other three channels: $J/\psi \to
\Lambda\overline{\Lambda}$, $J/\psi \to \Sigma^0\overline{\Sigma}^0$ and
$\psi(2S) \to \Lambda\overline{\Lambda}$. We define a model to explain the
origin of this phenomenon.
