Neutron and proton energy spectra from the non-mesonic weak decays of Λ 5He and Λ 12C

S. Okada; S. Ajimura; K. Aoki; A. Banu; H. C. Bhang; T. Fukuda; O. Hashimoto; J. I. Hwang; S. Kameoka; B. H. Kang; E. H. Kim; J. H. Kim; M. J. Kim; T. Maruta; Y. Miura; Y. Miyake; T. Nagae; M. Nakamura; S. N. Nakamura; H. Noumi; Y. Okayasu; H. Outa; H. Park; P. K. Saha; Y. Sato; M. Sekimoto; T. Takahashi; H. Tamura; K. Tanida; A. Toyoda; K. Tsukada; T. Watanabe; H. J. Yim

doi:10.1016/j.physletb.2004.07.031

Neutron and proton energy spectra from the non-mesonic weak decays of _Λ ⁵He and _Λ ¹²C

S. Okada, S. Ajimura, K. Aoki, A. Banu, H. C. Bhang, T. Fukuda, O. Hashimoto, J. I. Hwang, S. Kameoka, B. H. Kang, E. H. Kim, J. H. Kim, M. J. Kim, T. Maruta, Y. Miura, Y. Miyake, T. Nagae, M. Nakamura, S. N. Nakamura, H. NoumiY. Okayasu, H. Outa, H. Park, P. K. Saha, Y. Sato, M. Sekimoto, T. Takahashi, H. Tamura, K. Tanida, A. Toyoda, K. Tsukada, T. Watanabe, H. J. Yim

SCI - Physics

Research output: Contribution to journal › Article › peer-review

64 Citations (Scopus)

Abstract

We have simultaneously measured the energy spectra of neutrons and protons emitted in the non-mesonic weak decays of _Λ ⁵He and _Λ ¹²C hypernuclei produced via the (π ⁺, K ⁺) reaction with much higher statistics than 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, Γ _n(Λn→nn)/Γ _p(Λp→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 _Λ ⁵He.

Original language	English
Pages (from-to)	249-256
Number of pages	8
Journal	Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
Volume	597
Issue number	3-4
DOIs	https://doi.org/10.1016/j.physletb.2004.07.031
Publication status	Published - 2004 Sept 16

Keywords

Non-mesonic weak decay
Nucleon energy spectrum
Λ hypernuclei

ASJC Scopus subject areas

Nuclear and High Energy Physics

Access to Document

10.1016/j.physletb.2004.07.031

Cite this

Okada, S., Ajimura, S., Aoki, K., Banu, A., Bhang, H. C., Fukuda, T., Hashimoto, O., Hwang, J. I., Kameoka, S., Kang, B. H., Kim, E. H., Kim, J. H., Kim, M. J., Maruta, T., Miura, Y., Miyake, Y., Nagae, T., Nakamura, M., Nakamura, S. N., ... Yim, H. J. (2004). Neutron and proton energy spectra from the non-mesonic weak decays of _Λ ⁵He and _Λ ¹²C. Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 597(3-4), 249-256. https://doi.org/10.1016/j.physletb.2004.07.031

Okada, S, Ajimura, S, Aoki, K, Banu, A, Bhang, HC, Fukuda, T, Hashimoto, O, Hwang, JI, Kameoka, S, Kang, BH, Kim, EH, Kim, JH, Kim, MJ, Maruta, T, Miura, Y, Miyake, Y, Nagae, T, Nakamura, M, Nakamura, SN, Noumi, H, Okayasu, Y, Outa, H, Park, H, Saha, PK, Sato, Y, Sekimoto, M, Takahashi, T, Tamura, H, Tanida, K, Toyoda, A, Tsukada, K, Watanabe, T & Yim, HJ 2004, 'Neutron and proton energy spectra from the non-mesonic weak decays of _Λ ⁵He and _Λ ¹²C', Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, vol. 597, no. 3-4, pp. 249-256. https://doi.org/10.1016/j.physletb.2004.07.031

@article{a5597af263b44b29aa6ae9a76615b6a9,

title = "Neutron and proton energy spectra from the non-mesonic weak decays of Λ 5He and Λ 12C",

abstract = "We have simultaneously measured the energy spectra of neutrons and protons emitted in the non-mesonic weak decays of Λ 5He and Λ 12C hypernuclei produced via the (π +, K +) reaction with much higher statistics than 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, Γ n(Λn→nn)/Γ p(Λp→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 Λ 5He.",

keywords = "Non-mesonic weak decay, Nucleon energy spectrum, Λ hypernuclei",

author = "S. Okada and S. Ajimura and K. Aoki and A. Banu and Bhang, {H. C.} and T. Fukuda and O. Hashimoto and Hwang, {J. I.} and S. Kameoka and Kang, {B. H.} and Kim, {E. H.} and Kim, {J. H.} and Kim, {M. J.} and T. Maruta and Y. Miura and Y. Miyake and T. Nagae and M. Nakamura and Nakamura, {S. N.} and H. Noumi and Y. Okayasu and H. Outa and H. Park and Saha, {P. K.} and Y. Sato and M. Sekimoto and T. Takahashi and H. Tamura and K. Tanida and A. Toyoda and K. Tsukada and T. Watanabe and Yim, {H. J.}",

note = "Funding Information: We are grateful to Prof. K. Nakamura and the KEK-PS staff for support of the present experiment. We also acknowledge the staff members of the cryogenic group at KEK. This work was supported in part under the Korea–Japan collaborative research program of KOSEF(R01-2000-000-00019-0) and KRF(2003-070-C00015). ",

year = "2004",

month = sep,

day = "16",

doi = "10.1016/j.physletb.2004.07.031",

language = "English",

volume = "597",

pages = "249--256",

journal = "Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics",

issn = "0370-2693",

publisher = "Elsevier",

number = "3-4",

}

TY - JOUR

T1 - Neutron and proton energy spectra from the non-mesonic weak decays of Λ 5He and Λ 12C

AU - Okada, S.

AU - Ajimura, S.

AU - Aoki, K.

AU - Banu, A.

AU - Bhang, H. C.

AU - Fukuda, T.

AU - Hashimoto, O.

AU - Hwang, J. I.

AU - Kameoka, S.

AU - Kang, B. H.

AU - Kim, E. H.

AU - Kim, J. H.

AU - Kim, M. J.

AU - Maruta, T.

AU - Miura, Y.

AU - Miyake, Y.

AU - Nagae, T.

AU - Nakamura, M.

AU - Nakamura, S. N.

AU - Noumi, H.

AU - Okayasu, Y.

AU - Outa, H.

AU - Park, H.

AU - Saha, P. K.

AU - Sato, Y.

AU - Sekimoto, M.

AU - Takahashi, T.

AU - Tamura, H.

AU - Tanida, K.

AU - Toyoda, A.

AU - Tsukada, K.

AU - Watanabe, T.

AU - Yim, H. J.

N1 - Funding Information: We are grateful to Prof. K. Nakamura and the KEK-PS staff for support of the present experiment. We also acknowledge the staff members of the cryogenic group at KEK. This work was supported in part under the Korea–Japan collaborative research program of KOSEF(R01-2000-000-00019-0) and KRF(2003-070-C00015).

PY - 2004/9/16

Y1 - 2004/9/16

N2 - We have simultaneously measured the energy spectra of neutrons and protons emitted in the non-mesonic weak decays of Λ 5He and Λ 12C hypernuclei produced via the (π +, K +) reaction with much higher statistics than 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, Γ n(Λn→nn)/Γ p(Λp→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 Λ 5He.

AB - We have simultaneously measured the energy spectra of neutrons and protons emitted in the non-mesonic weak decays of Λ 5He and Λ 12C hypernuclei produced via the (π +, K +) reaction with much higher statistics than 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, Γ n(Λn→nn)/Γ p(Λp→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 Λ 5He.

KW - Non-mesonic weak decay

KW - Nucleon energy spectrum

KW - Λ hypernuclei

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U2 - 10.1016/j.physletb.2004.07.031

DO - 10.1016/j.physletb.2004.07.031

M3 - Article

AN - SCOPUS:4344632965

SN - 0370-2693

VL - 597

SP - 249

EP - 256

JO - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics

JF - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics

IS - 3-4

ER -