  Our exploratory study looks for direct access to the resonant hadronic
transition amplitude without resorting to the L\"uscher formalism. We study the
decay $\Psi(3770)\to\bar{D}D$ by applying partially twisted boundary conditions
to the quenched charm quark, circumventing possible problems with final state
interactions. If successful, we could compute the dependence of the transition
amplitude on the charm-quark mass and test the predictions made by
phenomenological quark-pair-creation models. Finally, we study if and to what
extent an extraction of the excited state $\Psi(3770)$ is necessary for this
analysis.
