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

Abstract

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

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