Study of thep¯d→psp¯pπ−Reaction at 5.5GeVc

Abstract

Based on 150 000 photographs taken with the 30-in. bubble chamber at the ZGS, we present a study of the $\overline{p}d\to p_s\overline{p}p{\pi }^{-}$ reaction. Important production of ${\overline{\Delta }}^{--}\mathrm{}\left(1236\right)\mathrm{}$ is observed. The distribution of the momentum transfer between the incident $\overline{p}$ and the final ${\overline{\Delta }}^{--}\mathrm{}\left(1236\right)\mathrm{}$ is compared with data at other energies and also with the crossed $\mathrm{pp}\to {\Delta }^{++}n$ reaction. That the peaking of the momentum transfer tends to be greater for the $\mathrm{pp}\to {\Delta }^{++}n$ than for the $\overline{p}n\to {\overline{\Delta }}^{--}p$ reaction at 5.5 $\frac{\mathrm{GeV}}{c}$ can be explained by using a simple Regge-pole model. For events produced without resonance in the final state, the longitudinal phase-space analysis is applied to the data. For these events, an attempt was also made to use a double Regge-pole model to describe the production. The present version of this model reproduces the experimental data fairly well. Using the Fermi motion of the neutron target, we try to extract information about the variation of the $\overline{p}n\to \overline{p}p{\pi }^{-}$ cross section with c.m. energy. In connection with this problem, a discussion on the validity domain of the impulse approximation is given.