The Contribution of One-Photon Annihilation at psi(2S) in e+e-   Experiment
  The continuum one-photon annihilation at psi(2S) in e+e- experiment is studied. Such contributions to the measured final state omega pi0 and pi+pi- at psi(2S) mass are estimated by phenomenological models. It is found that these contributions must be taken into account in the determination of branching ratios of psi(2S) --> omega pi0 and psi(2S) --> pi+ pi-, as well as other electromagnetic decay modes. The study reaches the conclusion that in order for BES to obtain the correct branching ratios on these decay modes, at least 10 inverse pb of data below the psi(2S) peak is needed. 
P.Wang, C.Z.Yuan, X.H.Mo