Meson Production in Deuterium by 1.4-Bev Pions

Pion-nucleon interactions have been produced in a deuterium-filled diffusion cloud chamber operated in the 1.37-Bev ${\pi }^{-}$ beam at the Cosmotron in order to compare the characteristics of ${\pi }^{-}-n$ and ${\pi }^{-}-p$ collisions. A total of 180 interactions have been observed and analyzed, and the total cross section for ${\pi }^{-}-d$ collisions is estimated to be 72±15 millibarns. The results are consistent with approximately equal ${\pi }^{-}-p$ and ${\pi }^{-}-n$ cross sections and a ratio of elastic: inelastic events=1:2 for both types of interaction. Approximately 15% of the inelastic collisions are cases in which two or more mesons are produced. Analysis of distributions of angles, momenta, and charges suggests a process for meson production in which the statistical model is slightly modified by a specific meson-nucleon interaction. The observed ratio of ${\pi }^{-}-n$ charge states $\left(n{\pi }^{-}{\pi }^0\right):\left(p{\pi }^{-}{\pi }^{-}\right)=(1.8\mathrm{}\pm 0.6):1$ indicates that interactions proceeding through the isotopic spin $T=\frac{3}{2}$ do not predominate. The prominence of ($p{\pi }^{-}{\pi }^{-}$) and ($p{\pi }^{-}{\pi }^0$) charge states together with a lack of correlation between emitted pion directions suggests that neither $T=0\mathrm{}$ nor $T=1\mathrm{}$ $\pi -\pi$ resonances play a significant role at this energy.