title: Observation of enhanced monopole strength and clustering in (12)Be.
abstract: In a recent breakup-reaction experiment using a Be12 beam at 29  MeV/nucleon, the 0+ band head of the expected He4+He8 molecular rotation was clearly identified at about 10.3 MeV, from which a large monopole matrix element of 7.0±1.0  fm2 and a large cluster-decay width were determined for the first time. These findings support the picture of strong clustering in Be12, which has been a subject of intense investigations over the past decade. The results were obtained thanks to a specially arranged detection system around zero degrees, which is essential in determining the newly emphasized monopole strengths to signal the cluster formation in a nucleus.
authors.affiliation: State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871, China.
authors.forename: Z H
authors.initials: ZH
authors.lastname: Yang
authors.affiliation: State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871, China.
authors.forename: Y L
authors.initials: YL
authors.lastname: Ye
authors.affiliation: State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871, China.
authors.forename: Z H
authors.initials: ZH
authors.lastname: Li
authors.affiliation: State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871, China.
authors.forename: J L
authors.initials: JL
authors.lastname: Lou
authors.affiliation: Institute of Modern Physics, Chinese Academy of Science, Lanzhou 730000, China.
authors.forename: J S
authors.initials: JS
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871, China.
authors.forename: D X
authors.initials: DX
authors.lastname: Jiang
authors.affiliation: State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871, China.
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authors.initials: YC
authors.lastname: Ge
authors.affiliation: State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871, China.
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authors.initials: QT
authors.lastname: Li
authors.affiliation: State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871, China.
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authors.initials: H
authors.lastname: Hua
authors.affiliation: State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871, China.
authors.forename: X Q
authors.initials: XQ
authors.lastname: Li
authors.affiliation: State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871, China.
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authors.initials: FR
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871, China.
authors.forename: J C
authors.initials: JC
authors.lastname: Pei
authors.affiliation: State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871, China.
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authors.initials: R
authors.lastname: Qiao
authors.affiliation: State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871, China.
authors.forename: H B
authors.initials: HB
authors.lastname: You
authors.affiliation: State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871, China and RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
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authors.initials: H
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871, China.
authors.forename: Z Y
authors.initials: ZY
authors.lastname: Tian
authors.affiliation: State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871, China.
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authors.initials: KA
authors.lastname: Li
authors.affiliation: State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871, China.
authors.forename: Y L
authors.initials: YL
authors.lastname: Sun
authors.affiliation: State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871, China and RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
authors.forename: H N
authors.initials: HN
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871, China.
authors.forename: J
authors.initials: J
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871, China and RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
authors.forename: J
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authors.lastname: Wu
authors.affiliation: State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871, China.
authors.forename: J
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authors.affiliation: State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871, China.
authors.forename: W
authors.initials: W
authors.lastname: Jiang
authors.affiliation: State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871, China and RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
authors.forename: C
authors.initials: C
authors.lastname: Wen
authors.affiliation: State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871, China.
authors.forename: B
authors.initials: B
authors.lastname: Yang
authors.affiliation: Institute of Modern Physics, Chinese Academy of Science, Lanzhou 730000, China.
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authors.initials: YY
authors.lastname: Yang
authors.affiliation: Institute of Modern Physics, Chinese Academy of Science, Lanzhou 730000, China.
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authors.affiliation: Institute of Modern Physics, Chinese Academy of Science, Lanzhou 730000, China.
authors.forename: J B
authors.initials: JB
authors.lastname: Ma
authors.affiliation: Institute of Modern Physics, Chinese Academy of Science, Lanzhou 730000, China.
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authors.initials: SL
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authors.affiliation: Institute of Modern Physics, Chinese Academy of Science, Lanzhou 730000, China.
authors.forename: J L
authors.initials: JL
authors.lastname: Han
authors.affiliation: RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
authors.forename: J
authors.initials: J
authors.lastname: Lee