Study of the Coherentp¯d→n¯dπ−Reaction at 5.55 GeV/c

Based on 150 000 photographs an analysis of the $\overline{p}d\to \overline{n}d{\pi }^{-}$ reaction is presented. Cross sections for all the coherent channels obtained from this exposure are also given. The interpretations of the $\overline{n}{\pi }^{-}$ enhancement at $M_{\overline{n} \pi }\sim 1.3$ GeV/${\mathit{c}}^2$ and the $d^{*}$ bump at 2.16 GeV/${\mathit{c}}^2$ observed in the $\overline{p}d\to \overline{n}d{\pi }^{-}$ reaction are discussed. Peripheral-type models are used in order to describe some production features of the $\overline{p}d\to \overline{n}d{\pi }^{-}$ reaction. The diffraction-dissociation aspect of the present data is discussed. Helicity conservation in the $s$ or $t$ channel is tested for the $\overline{p}d\to \overline{n}d {\pi }^{-}$ channel and also for the $\overline{p}d\to \overline{p}d {\pi }^{+}{\pi }^{-}$ and $\overline{p}d\to \mathrm{Nd}3\mathrm{}\pi$ reactions.