Zhao, Q (reprint author), Chinese Acad Sci, Inst High Energy Phys, Beijing 100049, Peoples R China.
The electromagnetic decay contributions to J/ psi(psi') -> VP, where V and P stand for vector and pseudoscalar meson, respectively, are investigated in a vector meson dominance (VMD) model. We show that J/psi(psi) -> gamma* -> VP can be constrained well with the available experimental information. We find that this process has significant contributions in psi' -> VP and may play a key role in understanding the deviations from the so-called "12% rule" for the branching ratio fractions between psi -> VP and J/psi -> VP. We also address that the "12% rule" becomes very empirical in exclusive hadronic decay channels. (c) 2006 Elsevier B.V. All rights reserved.