Comprehensive calculations on the OZI-forbidden nonleptonic decays of orthoquarkonia J/ψ(ϒ)→ππ,ρπ

In this work, we calculate the decay rates of the OZI-forbidden processes J/ψ(ϒ)→ππ,ρπ at the order of the leading-twist distribution amplitude. The process of J/ψ(ϒ)→π+π− violates isospin conservation and the amplitude is explicitly proportional to the isospin violation factor mu−md, our numerical results on their decay rates are consistent with the data. The process J/ψ(ϒ)→ρπ violates the hadronic helicity conservation and should be suppressed, as indicated in literature, its decay rate can only be proportional to at the order of leading twist. Our theoretical evaluation confirms this statement that the theoretical evaluation on Γ(J/ψ(ϒ)→ρπ) is almost one order smaller than the data unless the model parameters take certain extreme values. It may imply that the sizable branching ratio of J/ψ(ϒ)→ρπ should be explained by either higher twist contributions or other mechanisms.