Analysis of the angular distribution of the baryons, and decay products, produced in $e^+e^-\to J/\psi, \psi(2S) \to \Sigma^+\bar\Sigma^-$. Gives information about the decay and is useful for testing correlations in hadron decays. N.B. The moment data is not corrected for efficiency/acceptance and should therefore only be used qualatively. Beam energy must be specified as analysis option "ENERGY" when rivet-merging samples.