Decays of the J/$\psi$ to $\Lambda \overline{\Lambda}, \Lambda \overline{\Lambda}\gamma$ and $\Lambda \overline{\Lambda}\pi^0$ final states

With 7.8 million produced J / ψ events collected by the BES detector at the BEPC, decays J/ψ→Λ Λ ,Λ Λ γ and Λ Λ π 0 are analysed. The branching ratios are measured to be Br (J/ψ→Λ Λ )=(1.08±0.06±0.24)×10 −3 , Br (J/ψ→Λ Λ γ)<1.6×10 −4 (90% C.L. ) , Br (J/ψ→Λ Λ π 0 )=(2.3±0.7±0.8)×10 −4 , respectively. The angular distribution for J/ψ→Λ Λ is of the form d N d cos θ =N 0 (1+α cos 2 θ) , from which we determine α =0.52±0.33±0.13.