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تسجيل مستخدم جديدNeutron and proton energy spectra from the non-mesonic weak decays of 5_Lambda-He and 12_Lambda-C
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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.
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We have measured both yields of neutron-proton and neutron-neutron pairs emitted from the non-mesonic weak decay process of 5_Lambda-He and 12_Lambda-C hypernuclei produced via the (pi^+,K^+) reaction for the first time. We observed clean back-to-bac
k correlation of the np- and nn-pairs in the coincidence spectra for both hypernuclei. The ratio of those back-to-back pair yields, Nnn / Nnp, must be close to the ratio of neutron- and proton-induced decay widths of the decay, Gn(Lambda n -> nn)/Gp(Lambda p -> np). The obtained ratios for each hypernuclei support recent calculations based on short-range interactions.
The Non-Mesonic (NM) decay of $^4_Lambda{mathrm{He}}$ and $^5_Lambda{mathrm{He}}$ in two-body channels has been studied by the FINUDA Collaboration. Two-body NM decays of hypernuclei are rare and the existing observations and theoretical calculations
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We precisely measured pi^0 branching ratios of 5_Lambda-He and 12_Lambda-C hypernuclei produced via (pi^+,k^+) reaction. Using these pi^0 branching ratios with the pi^- branching ratios and the lifetimes, we obtained the pi^0 decay widths and the non
-mesonic weak decay widths at high statistics with the accuracy of ~5 % (stat) for both hypernuclei.
The results of a measurement of the proton spectra following the Non--Mesonic Weak Decay of $mathrm{^5_{Lambda}He}$, $mathrm{^7_{Lambda}Li}$ and $mathrm{^{12}_{Lambda}C}$ are presented and discussed. The experiment was performed at the ($e^+$ $e^-$)
collider DA$Phi$NE at Laboratori Nazionale di Frascati of INFN. It is the first measurement for $mathrm{^7_{Lambda}Li}$, 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 $Lambda p to np$ 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 $mathrm{^5_{Lambda}He}$ is somehow similar to the ones reported by previous measurements and theoretical calculations, but the same doesnt happen for the $mathrm{^{12}_{Lambda}C}$ one.
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(Lamb
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