Schrödinger Bootstrap Model

A Schrödinger-equation model for the process $K\overline{K}\to \varphi$ is solved numerically. The potential used is that given by one-$\varphi$ exchange and an ($S{U}_3$-determined) one-$\rho$ exchange. The coupling constant is fitted to give a resonance at the $\varphi$ mass. The resulting cross-channel width is consistent with the direct-channel (Schrödinger) width. The discrepancy from the experimental width is similar to that present in $S$-matrix calculations. No cutoff is required.