π − p → π − π + π − p Reaction at 6 GeV/ c

This report is based on the study of 2300 events representing the ${\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}p$ final state produced by the interactions of 5.97-GeV/c ${\ensuremath{\pi}}^{\ensuremath{-}}$ mesons with protons in the Argonne National Laboratory 30-in. hydrogen bubble chamber. This final state has a cross section of 1.39\ifmmode\pm\else\textpm\fi{}0.15 mb and is dominated by ${\ensuremath{\rho}}^{0}$ production (0.60\ifmmode\pm\else\textpm\fi{}0.08 mb) and ${\ensuremath{\Delta}}^{++}(1236)$ production (0.39\ifmmode\pm\else\textpm\fi{}0.06 mb). There is evidence for the production of ${A}_{1}$ and ${A}_{1.5}$ mesons in the $3\ensuremath{\pi}$ mass spectrum in addition to the ${A}_{2}$. Some characteristics of the $\ensuremath{\pi}\ensuremath{\rho}p$ and $\ensuremath{\pi}\ensuremath{\pi}\ensuremath{\Delta}$ final states can be explained with a double-Regge-exchange model.