Proton spectra from Non-Mesonic Weak Decay of p-shell Lambda-Hypernuclei and evidence for the two-nucleon induced process

New spectra from the FINUDA experiment of the Non Mesonic Weak Decay (NMWD) proton kinetic energy for 9(Lambda)Be, 11(Lambda)B, 12(Lambda)C, 13(Lambda)C, 15 (Lambda)N and 16(Lambda)O are presented and discussed along with the published data on 5(Lambda)He and 7(Lambda)Li. Exploiting the large mass number range and the low energy threshold (15 MeV) for the proton detection of FINUDA, an evaluation of both Final State Interactions (FSI) and the two nucleon induced NMWD contributions to the decay process has been done. Based on this evaluation, a linear dependence of FSI on the hypernuclear mass number A is found and for the two nucleon stimulated decay rate the experimental value of Gamma2/Gammap=0.43+-0.25 is determined for the first time. A value for the two nucleon stimulated decay rate to the total decay rate Gamma2/GammaNMWD=0.24+-0.10 is also extracted.Comment: 11 pages and 2 figure

New results on mesonic weak decay of p-shell Λ-hypernuclei

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Correlated Λt\Lambda t pairs from the absorption of K−K^- at rest in light nuclei

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 $\Lambda t$ correlations. Regardless of $A$, the $\Lambda t$ pairs are preferentially emitted in opposite directions. Reaction modeling predominantly assigns to the $K^-_{stop}A\to\Lambda t(N)A'$ direct reactions the emission of the $\Lambda t$ pairs whose yield is found to range from $10^{-3}$ to $10^{-4}$$/K^-_{stop}$. The experiment was performed with the FINUDA spectrometer at DA$\Phi$NE (LNF).Comment: 11 pages, 5 figures, accepted for publication in Phys. Lett.

New results on Mesonic Weak Decay of pp-shell LambdaLambda-Hypernucle

The FINUDA experiment performed a systematic study of the charged mesonic weak decay channel of 7Λ Li and 5/2+ for 11 ΛB ground-state are confirmed and a spin-parity 3/2+ for 15 ΛN ground-state is assigned for the first time. p-shell Λ-hypernuclei. Negatively charged pion spectra from mesonic decay were measured with magnetic analysis for the first time for 7Λ Li, 9 ΛBe, 11 ΛB and 15 ΛN. 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 Γπ−/Γtot were derived from the measured spectra and converted to π− decay rates Γπ− 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+ fo

Mesonic and Non-Mesonic Weak Decay of Hypernuclei with FINUDA

The FINUDA experiment performed a systematic study of both mesonic and non-mesonic weak decay of p-shell Λ-hypernuclei. Recent results on the mesonic decay rates and the non-mesonic decay ratios are illustrated and briefly discussed. © 2009 Elsevier B.V. All rights reserved

Recent results on mesonic weak decay of Λ-hypernuclei

The FINUDA experiment has performed a systematic study of mesonic weak decay of p-shell Λ-hypernuclei. Recent results on the mesonic decay spectra and ratios are illustrated and discussed

Recent results on mesonic weak decay of Lambda-Hypernuclei

The FINUDA experiment had performed a systematic study of mesonic weak decay of p-shell Lambda-hypernuclei. Recent results on the mesonic decay spectra and ratios are illustrated and discussed

NEW RESULTS ON NONMESONIC WEAK DECAY OF Λ HYPERNUCLEI WITH FINUDA

The FINUDA experiment has performed a systematic study of the NonMesonic Weak Decay (NMWD) of hypernuclei analizing all the data collected from 2003 up to 2007. The results of a measurement of the spectra of protons coming from the NMWD of 5He, 7Li, 9Be, 11 B, 12 C, 13 C, 15 N and 16 O are the subject of this paper