Observation of eta(c) decay into Sigma(+)(Sigma)over-bar(-) and (sic)(-)over bar>(+) final states

Using a data sample of 2.25 x 10(8) J/psi events collected with the BESIII detector, we present the first observation of the decays of eta(c) mesons to Sigma(+)( Sigma) over bar (-) and (sic)(-)(+) .The branching fractionsare measured to be (2.11 +/- 0.28( stat) +/- 0.18(syst) +/- 0.50(PDG)) x 10(-3) and (0.89 +/- 0.16( stat) +/- 0.08(syst) +/- 0.21(PDG)) x 10(-3) for eta(c) -> Sigma(+)( Sigma) over bar (-) and (sic)(-)(+) , respectively. These branching fractionsprovide important information on the helicity selection rulein charmonium- decay processes. DOI: 10.1103/PhysRevD.87.012003