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. Ozawa
  • T. 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
*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

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
StatePublished - 22 Jan 2004
Externally publishedYes

Keywords

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

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