First Experimental Determination of the One-Proton Induced Non-Mesonic Weak Decay Width forp-shell Λ-hypernuclei

A further study of the FINUDA data about non-mesonic weak decay of eight Λ-hypernuclei in the A range (5 – 16) was carried out. New values of the ratio between the two-nucleon and the one-proton induced decay widths, Γ2N /Γp, were determined from single proton spectra, Γ2N /Γp = 0.50 ± 0.24, and from neutron and proton coincidence spectra, Γ /Γ 2N p A further study of the FINUDA data about non-mesonic weak decay of eight Λ-hypernuclei in the A range (5 – 16) was carried out. New values of the ratio between the two-nucleon and the one-proton induced decay widths, Γ2N /Γp, were determined from single proton spectra, Γ2N /Γp = 0.50 ± 0.24, and from neutron and proton coincidence spectra, Γ /Γ 2N p= 0.36 ± 0.14 +0.05sys , in full agreement stat −0.04sys with the previously published ones. Starting from these values, a method was developed to extract the one-proton induced decay width in units of the free Λ decay width, Γp/ΓΛ, without resorting to Intra-Nuclear Cascade models but by exploiting measured quantities only and by assuming a linear dependence on A of the effects due to Final State Interaction. The present work is the first systematic Γp/ΓΛ determination ever done and it agrees with recent theoretical predictions within the errors.