Search for the C-parity violating process J/ψ →γγ via γ(2S) -π+π-J / ψ

Using 14.0 x10 6 ψ(25) events collected with the BES-II detector, the C-parity violating process 7/ψ→ yy via ψ(2S) → π + π - J/ψ is studied. We determine a new upper limit for the J/ψ→ γγ branching ratio of B(J/ψ →γγ) < 2.2 X 10 -5 at the 90% C.L., which is about 20 times lower than the previous measurement.