COMMENT ON THE CALCULATIONS FOR SOME BOUND-STATE ANNIHILATION AND CREATION

For a process, involving annihilation or creation of a (quark-antiquark pair) bound state with two or more vertices i.e. at least there is one propagator in the corresponding Feynman diagram(s), we point out that the bound state effects in such a process need to be treated more precisely if requiring a more accurate estimate, due to the propagator(s) involved, rather than to make so crude approximation, to attribute the effects so simple as a factor proportional to the wavefunction at origin of the bound state into the amplitude of the process finally.