Neutron and proton energy spectra from the non-mesonic weak decays of   5_Lambda-He and 12_Lambda-C
  We have simultaneously measured the energy spectra of neutrons and protons emitted in the non-mesonic weak decays of 5_Lambda-He and 12_Lambda-C hypernuclei produced via the (pi^+,k^+) reaction with much higher statistics over those of previous experiments. The neutron-to-proton yield ratios for both hypernuclei at a high energy threshold (60 MeV) were approximately equal to two, which suggests that the ratio of the neutron- and proton-induced decay channels, Gn(Lambda n -> nn)/Gp(Lambda p -> np), is about 0.5. In the neutron energy spectra, we found that the yield of the low-energy component is unexpectedly large, even for 5_Lambda-He. 
S.Okada, S.Ajimura, K.Aoki, A.Banu, H.C.Bhang, T.Fukuda, O.Hashimoto,   J.I.Hwang, S.Kameoka, B.H.Kang, E.H.Kim, J.H.Kim, M....