Observation of "Peripheral" Backward Multipion Production at 2.15 BeV/c

Abstract

Using the Princeton-Pennsylvania Accelerator rapid-cycling bubble chamber in a flash-lamp triggered mode we have observed backward (${\pi }^{+}{\pi }^{-}$) and (${\pi }^{+}{\pi }^{-}{\pi }^0$) multipion production in the reaction ${\pi }^{+}n\to pm\left(\pi \right)$ at 2.15 BeV/c. The main characteristics of the data are a sharp forward peaking of the proton relative to the incident ${\pi }^{+}$ direction for all multipion masses below 1100 MeV/c and the strong production of the $\omega$ meson. Backward $\omega$ production is observed to be more probable than backward $\rho$ production. The sharp forward peaking of the proton in these reactions is suggestive of the dominance of baryon exchange.