Physics Letters B for the first time. A value for the two-nucleon stimulated decay rate to the total decay rate Γ2/ΓNMWD=0.24±0.10 is also extracted.

The FINUDA experiment performed a systematic study of the charged mesonic weak decay channel of p-shell Λ-hypernuclei. Negatively charged pion spectra from mesonic decay were measured with magnetic analysis for the first time for 7 Λ Li, 9 Λ Be, 11 Λ B and 15 Λ N. The shape of the π − spectra was interpreted through a comparison with pion distorted wave calculations that take into account the structure of both hypernucleus and daughter nucleus. Branching ratios Γ π − /Γtot were derived from the measured spectra and converted to π − decay rates Γ π − by means of known or extrapolated total decay widths Γtot of p-shell Λ-hypernuclei. Based on these measurements, the spin-parity assignment 1/2 + for 7 Λ Li and 5/2 + for 11 Λ B ground-state are confirmed and a spin-parity 3/2 + for 15 Λ N ground-state is assigned for the first time.

The results of a measurement of the proton spectra following the Non-Mesonic Weak Decay of 5 Λ He, 7 Λ Li and 12 Λ C are presented and discussed. The experiment was performed at the (e + e − ) collider DAΦNE at Laboratori Nazionale di Frascati of INFN.It is the first measurement for 7 Λ Li, and for all the spectra the lower limit on the energy of the protons is 15 MeV, never reached before. All the spectra show a similar shape, namely a peak at around 80 MeV as expected for the free Λp → np weak reaction, with a low energy rise that should be due to Final State Interactions and/or two-nucleon induced weak processes. The decay spectrum of 5 Λ He is somehow similar to the ones reported by previous measurements and theoretical calculations, but the same doesn't happen for the 12 Λ C one.

Novel data from the K − stop A absorption reaction in light nuclei 6,7 Li and 9 Be are presented. The study aimed at finding Λt correlations. Regardless of A, the Λt pairs are preferentially emitted in opposite directions. Reaction modeling predominantly assigns to the K − stop A → Λt(N )A ′ direct reactions the emission of the Λt pairs whose yield is found to range from 10 −3 to 10 −4 /K − stop . The experiment was performed with the FINUDA spectrometer at DAΦNE (LNF). :21.45.+v, 21.80.+a 25.80.Nv PACS

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