Investigation into the Elastic Scattering ofΣ±Hyperons on Hydrogen

Abstract

An investigation has been made into the elastic scattering of $\ensuremath{\Sigma}$ hyperons on hydrogen. The experiment was based on a sample of 12 000 $\ensuremath{\Sigma}$ particles formed in a propane bubble chamber by the interactions of 1.15-Bev/c ${K}^{\ensuremath{-}}$ mesons. A total track length of 210 meters in the energy range 100 to 700 Mev has been examined.Ten examples were found of the reaction ${\ensuremath{\Sigma}}^{+}+p\ensuremath{\rightarrow}{\ensuremath{\Sigma}}^{+}+p$, and six of the reaction ${\ensuremath{\Sigma}}^{\ensuremath{-}}+p\ensuremath{\rightarrow}{\ensuremath{\Sigma}}^{\ensuremath{-}}+p$. The estimates of the cross sections for the two processes are, respectively, ${38}_{\ensuremath{-}14}^{+18}$mb and ${10}_{\ensuremath{-}4}^{+6}$mb. The scattering angle distributions in the c.m. system appear isotropic for the ${\ensuremath{\Sigma}}^{+}$ particles, and peaked forward for the ${\ensuremath{\Sigma}}^{\ensuremath{-}}$ particles. The results are discussed in relation to various theoretical predictions, and, in particular, some evidence is found favoring the Gammel-Thaler method of treating the triplet odd-parity nucleon-nucleon potential.