Comment on the hadronic decay of excited heavy quarkonia
  We make comments on ref.[Z.Phys. C73, 541 (1997)], and provide partial wave analysis to the decays of excited heavy S-wave $1^-$ quarkonia into the basic $1^-$ quarkonia state plus $\pi\pi$. It is revealed that there exist contributions of D-wave transition in $\psi'\longrightarrow J/\psi\pi\pi$, $\Upsilon(2S)\longrightarrow \Upsilon(1S) \pi \pi$ and $\Upsilon(3S)\longrightarrow \Upsilon(1S) \pi \pi$ by using the data-fitting results in ref.[Z.Phys C73, 541 (1997)]. A possible experimental method to measure the D-wave directly is discussed. 
Mu-Lin Yan (ICTP, Trieste; USTC, Hefei) Yi Wei and Ting-Liang Zhuang   (USTC, Hefei)