7λLi ground-state spin determined by the yield of γ-rays subsequent to weak decay

J. Sasao, D. Abe, H. Akikawa, K. Araki, H. Bhang, T. Endo, Y. Fujii, T. Fukuda, O. Hashimoto, K. Imai, H. Hotchi, Y. Kakiguchi, J. H. Kim, Y. D. Kim, T. Miyoshi, T. Murakami, T. Nagae, H. Noumi, H. Outa, K. OzawaT. Saito, Y. Sato, S. Satoh, R. Sawafta, M. Sekimoto, T. Takahashi, H. Tamura, L. Tang, K. Tanida, H. H. Xia, S. H. Zhou, L. H. Zhu

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24 Citations (Scopus)

Abstract

Using a large-acceptance germanium detector array (Hyperball), we measured a γ-ray spectrum in coincidence with production of 7 λLi bound states in the 7Li(π+, K+) reaction. We observed a γ-ray peak at 429 keV due to the transition from the first excited state of 7Be produced by the weak decay of 7λLi, 7λLi → 7Be*(1/2-, 429 keV) + π-. From the yield of this γ-ray, the branching ratio of the 7 λLi weak decay to 7Be*(429) was obtained to be (6.0-1.6+1.3) x 10-2. Compared with theoretically calculated values of the partial decay rates, the measurement indicates that the ground-state spin of 7λLi is 1/ 2 but not 3/2.

Original languageEnglish
Pages (from-to)258-264
Number of pages7
JournalPhysics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
Volume579
Issue number3-4
DOIs
Publication statusPublished - 2004 Jan 22

Keywords

  • Mesonic decay
  • Λ hypemuclei
  • ΛN interaction
  • γ spectroscopy

ASJC Scopus subject areas

  • Nuclear and High Energy Physics

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