Rates for the reactions antiproton-proton --> pi phi and gamma phi

Abstract

We study antiproton-proton annihilation at rest into $\ddot{I}€\ddot{I}•$ and ${\hat{I}}^3\ddot{I}•$. Rescattering by $\overline{K^{\ast }}K+K^{\ast }\overline{K}$ and $\ddot{I}{}^{+}\ddot{I}{}^{-}$ for $\overline{p}p\to \ddot{I}€\ddot{I}•$ states is sizable, of order $(0.90\mathrm{to}2.6)\times 10^{-4}$ in the branching ratio, but smaller than experiment. For $\overline{p}p\to {\hat{I}}^3\ddot{I}•$ the rescattering contributions are negligible, but the ${\hat{I}}^3\ddot{I}•$ channel is well explained by a $\ddot{I}\ddot{I}•$ intermediate state combined with vector meson dominance.

12 pages, plain latex, 2 postscript figures available upon request, PSI-PR-93-20