arXiv subjects

T. Maruta

Publications and source records attributed to T. Maruta.

23 records · Page 2Linked to original sources

arXiv2004

Nucleon-nucleon coincidence measurement in the non-mesonic weak decay of 5_Lambda-He and 12_Lambda-C hypernuclei

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-back 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.

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arXiv2004

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.

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arXiv2004

Measurement of the $π^-$ decay width of $^5_Λ$He

We have precisely measured $Λ\to pπ^-$ decay width of \5LHe and demonstrated significantly larger $α$ -$Λ$ overlap than expected from the central repulsion $α$-$Λ$ potential, which is derived from YNG Λ$-nucleon interaction.

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arXiv2004

pi^0 decay branching ratios of 5_Lambda-He and 12_Lambda-C hypernuclei

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.

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arXiv2004

Proton asymmetry in non-mesonic weak decay of light hypernuclei

We have obtained the decay asymmetry parameters in non-mesonic weak decay of polarized Lambda-hypernuclei by measuring the proton asymmetry. The polarized Lambda-hypernuclei, 5_Lambda-He, 12_Lambda-C, and 11_Lambda-B, were produced in high statistics via the (pi^+,k^+) reaction at 1.05 GeV/c in the forward angles. Preliminary analysis shows that the decay asymmetry parameters are very small for these s-shell and p-shell hypernuclei.

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