Study of ππ final state interactions in ψ(2S)→π+π− J/ψ

The π+π− transition of heavy quarkonia in decay ψ(2S)→π+π− J/ψ is studied. With the BESII data on the decay ψ(2S) → π+π− J/ψ, we update the values of coupling constants (gi) and chromopolarizability (αψ(2S)J/ψ) in this process.