π−pInteractions at 10 GeV/cwith Four Charged Secondaries

Abstract

About 800 ${\ensuremath{\pi}}^{\ensuremath{-}}p$ interactions with four charged secondaries produced by 10.25-GeV/c negative pions in the 81-cm Saclay hydrogen bubble chamber have been analyzed. The cross sections for the various reactions, including the production of ${N}^{*}$, $\ensuremath{\rho}$, and $\ensuremath{\omega}$ are given in Tables I and III. The c.m.-system angular and momentum distributions are discussed; the nucleons are strongly peaked backward whereas the pions, especially the ${\ensuremath{\pi}}^{\ensuremath{-}}$, go predominantly forward. Values for the average transverse momentum of the various secondary particles have been determined. From plots of the average transverse momentum versus the c.m.-system longitudinal momentum correlations between the momentum ${p}^{*}$ and the scattering angle ${\ensuremath{\Theta}}^{*}$ can be seen; it is found that ${p}^{*}$ is essentially proportional to the inverse of ${sin\ensuremath{\Theta}}^{*}$. The occurrence of resonant states has been investigated. Production of ${\ensuremath{\rho}}^{0}$ seems very important at this energy in the $p{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ final state. Production of ${N}^{*++}$ is relatively more important in final states involving additional pions and a proton.