Upper Limit on theω→2πDecay Rate Fromp¯nAnnihilations at Rest

Abstract

Antiproton-neutron annihilations at rest ($L=0\mathrm{}$) into $G$-parity states of opposite sign are incoherent. This permits a measurement of the ratio $R=\frac{(\omega \to {\pi }^{+}{\pi }^{-})}{(\omega \to {\pi }^{+}{\pi }^{-}{\pi }^0)}$ in the absence of $\omega \mathrm{\rho }$ interference. In this way we find the upper limit $R<\mathrm{}4.3\%$ at the 97.5% confidence level ($\Delta {\chi }^2=4\mathrm{}$).