Capture of aK¯Meson from the2POrbit inHe4Followed byπ−andΛ0Production

The reaction $\overline{K}+{}_{}{}^4{}_{}{}^{}\mathrm{He}\to {\pi }^{-}+{\Lambda }^0+{}_{}{}^3{}_{}{}^{}\mathrm{He}$ is studied under the assumption of capture from the $2P$ Bohr orbit. The outgoing pion and the recoiling ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ momentum distributions are calculated with the inclusion of ${Y_1}^{*}$-resonance and $\Sigma -\Lambda$ conversion amplitudes. The $\Sigma -\Lambda$ conversion process is of particular importance. The main conclusion is that the pion spectrum tends to favor the assumption that the stopping $\overline{K}$ are captured from a $P$-state atomic orbit. The conclusion is consistent with the results of the $\overline{K}$-capture x-ray experiment of Burleson et al.