Polarization of the Σ0 Particles Produced in the Reaction π−+p→K0+Σ0 at 1.5 and 1.8 BeVc

The polarization of the ${\ensuremath{\Sigma}}^{0}$ particles produced in the reaction ${\ensuremath{\pi}}^{\ensuremath{-}}+p\ensuremath{\rightarrow}{K}^{0}+{\ensuremath{\Sigma}}^{0}$ has been measured at $1.5 \mathrm{and} 1.8 \frac{\mathrm{BeV}}{c}$, using a spark-chamber magnet system. The product ${\ensuremath{\alpha}}_{\ensuremath{\Lambda}}〈{\ensuremath{\sigma}}_{{\ensuremath{\Sigma}}^{0}}〉$ was found to be -0.47\ifmmode\pm\else\textpm\fi{}0.33, +0.51\ifmmode\pm\else\textpm\fi{}0.27, and +0.82\ifmmode\pm\else\textpm\fi{}0.44, respectively, in ${\ensuremath{\Sigma}}^{0}$ c.m. angular intervals centered at $cos{\ensuremath{\theta}}^{*}=0.8,\ensuremath{-}014$, and $0.0 \mathrm{at} 1.8 \frac{\mathrm{BeV}}{c}$; and -0.55\ifmmode\pm\else\textpm\fi{}0.23, -0.31\ifmmode\pm\else\textpm\fi{}0.38, and -0.82\ifmmode\pm\else\textpm\fi{}0.46 at the same production angles at $1.5 \frac{\mathrm{BeV}}{c}$. The ${\ensuremath{\Sigma}}^{0}$ production angular distributions in the backward hemisphere at both momenta are also given. Both polarization and angular distribution are found to vary rapidly with energy.