Doubly Coherent Production ofπ−byHe3Ions of 910 MeV

The inclusive pion spectrum from the reaction ${}_{}{}^3{}_{}{}^{}\mathrm{He}$+${}_{}{}^6{}_{}{}^{}\mathrm{Li}$→${\pi }^{-}+X$ at 910 MeV was measured at 0° with moderate resolution up to the kinematic limit of the two-body final-state reaction. A first analysis shows that the production of high-energy pions cannot be explained by the $\mathrm{NN}\to \mathrm{NN}\pi$ process using conventional nucleon momentum distributions. At the end of the spectrum a clear deviation from the general falloff slope is observed and attributed to the doubly coherent reaction ${}_{}{}^3{}_{}{}^{}\mathrm{He}$+${}_{}{}^6{}_{}{}^{}\mathrm{Li}$→${}_{}{}^9{}_{}{}^{}\mathrm{C}$+${\pi }^{-}$.