Study of diffraction dissociation of. pi. /sup -/ mesons in nucleons and nuclei at 200 GeV/c

A comparative study is made of the diffraction dissociation of ..pi../sup -/ mesons in protons and nuclei at a primary momentum 200 GeV/c. For selection and study of the diffraction dissociation of ..pi../sup -/ mesons in protons we used the parametrically invariant quantity g/sup prime//sub 1/. It is shown that the contribution of coherent diffraction dissociation of ..pi../sup -/ mesons in heavy nuclei of nuclear emulsion is approximately three times greater than in light nuclei. The criterion of ..beta../sub 2/-azimuthal correlations was used to estimate the cross section for coherent diffraction dissociation (..pi../sup -/..--> pi../sup -/..pi../sup -/..pi../sup +/), which turned out to be sigma-bar/sup prime/ = 5.7 +- 1.47 mb.