The bound-state level structures of the ${}_{\\ensuremath{\\Lambda}}^{16}$O and ${}_{\\ensuremath{\\Lambda}}^{15}$N hypernuclei were studied by \\ensuremath{\\gamma}-ray spectroscopy using a germanium detector array (Hyperball) via the $^{16}\\mathrm{O}$ (${K}^{\\ensuremath{-}},{\\ensuremath{\\pi}}^{\\ensuremath{-}}\\ensuremath{\\gamma}$) reaction. A level scheme for ${}_{\\ensuremath{\\Lambda}}^{16}$O was determined from the observation of three \\ensuremath{\\gamma}-ray transitions from the doublet of states (${2}^{\\ensuremath{-}},{1}^{\\ensuremath{-}}$) at $~6.7$ MeV to the ground-state doublet (${1}^{\\ensuremath{-}},{0}^{\\ensuremath{-}}$). The ${}_{\\ensuremath{\\Lambda}}^{15}$N hypernuclei were produced via proton emission from unbound states in ${}_{\\ensuremath{\\Lambda}}^{16}$O. Three \\ensuremath{\\gamma} rays were observed, and the lifetime of the $1/{2}^{+};1$ state in ${}_{\\ensuremath{\\Lambda}}^{15}$N was measured by the Doppler shift attenuation method. By comparing the experimental results with shell-model calculations, the spin dependence of the $\\ensuremath{\\Lambda}N$ interaction is discussed. In particular, the measured ${}_{\\ensuremath{\\Lambda}}^{16}$O ground-state doublet spacing of $26.4\\ifmmode\\pm\\else\\textpm\\fi{}1.6\\ifmmode\\pm\\else\\textpm\\fi{}0.5$ keV determines a small but nonzero strength of the $\\ensuremath{\\Lambda}N$ tensor interaction.

We have searched for neutrons from the 3‐body photon‐induced reaction 9Be + γ → α + α + n using bremsstrahlung produced by electrons from a 2‐MV Van de Graaff. The target was located within a block of beryllium surrounded by an array of 3He proportional counters embedded in paraffin. Based on energy and intensity calibrations of the accelerator and detector using the 9Be + γ → 8Be+n reaction, an upper limit of 93 nb (4σ) was placed on the cross section for neutron production between the 3‐body and 2‐body thresholds. This value is substantially below a previously experimental result using photoexcitation by a 142Pr gamma source and also below an earlier theoretical estimate. We suggest that bremsstrahlung due to beta rays between 1665 keV and the 2160‐keV end‐point of the 142Pr beta‐ray spectrum could account for the photoneutron yield in the 3‐body region that had previously been attributed to 142Pr gamma rays.

The (K-stopped, pi0) strangeness and charge changing reaction was investigated by producing a 12Blambda hypernucleus from a carbon target. The branching ratio for K- capture to the ground and p-shell states of this hypernucleus was found to be (0.28 +- 0.08)x10-3 and (0.35 +- 0.09)x10-3, respectively, which after correction for isospin was lower than a previously measured value for the 12C(K-stopped, pi-)12Clambda reaction, but still above the theoretical predictions for the ground state. The experiment obtained a missing-mass resolution comparable to in-flight reactions, however the higher background and lower selectivity of the K-stopped reaction limits its usefulness in experimental study of the 12C(K-stopped, pi0)12Blambda reaction.