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Enciu M, Liu HN, Obertelli A, Doornenbal P, Nowacki F, Ogata K, Poves A, Yoshida K, Achouri NL, Baba H, Browne F, Calvet D, Château F, Chen S, Chiga N, Corsi A, Cortés ML, Delbart A, Gheller JM, Giganon A, Gillibert A, Hilaire C, Isobe T, Kobayashi T, Kubota Y, Lapoux V, Motobayashi T, Murray I, Otsu H, Panin V, Paul N, Rodriguez W, Sakurai H, Sasano M, Steppenbeck D, Stuhl L, Sun YL, Togano Y, Uesaka T, Wimmer K, Yoneda K, Aktas O, Aumann T, Chung LX, Flavigny F, Franchoo S, Gasparic I, Gerst RB, Gibelin J, Hahn KI, Kim D, Kondo Y, Koseoglou P, Lee J, Lehr C, Li PJ, Linh BD, Lokotko T, MacCormick M, Moschner K, Nakamura T, Park SY, Rossi D, Sahin E, Söderström PA, Sohler D, Takeuchi S, Toernqvist H, Vaquero V, Wagner V, Wang S, Werner V, Xu X, Yamada H, Yan D, Yang Z, Yasuda M, Zanetti L. Extended p_{3/2} Neutron Orbital and the N=32 Shell Closure in ^{52}Ca. PHYSICAL REVIEW LETTERS 2022; 129:262501. [PMID: 36608181 DOI: 10.1103/physrevlett.129.262501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 10/24/2022] [Accepted: 11/23/2022] [Indexed: 06/17/2023]
Abstract
The one-neutron knockout from ^{52}Ca in inverse kinematics onto a proton target was performed at ∼230 MeV/nucleon combined with prompt γ spectroscopy. Exclusive quasifree scattering cross sections to bound states in ^{51}Ca and the momentum distributions corresponding to the removal of 1f_{7/2} and 2p_{3/2} neutrons were measured. The cross sections, interpreted within the distorted-wave impulse approximation reaction framework, are consistent with a shell closure at the neutron number N=32, found as strong as at N=28 and N=34 in Ca isotopes from the same observables. The analysis of the momentum distributions leads to a difference of the root-mean-square radii of the neutron 1f_{7/2} and 2p_{3/2} orbitals of 0.61(23) fm, in agreement with the modified-shell-model prediction of 0.7 fm suggesting that the large root-mean-square radius of the 2p_{3/2} orbital in neutron-rich Ca isotopes is responsible for the unexpected linear increase of the charge radius with the neutron number.
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Affiliation(s)
- M Enciu
- Institut für Kernphysik, Technische Universität Darmstadt, 64289 Darmstadt, Germany
| | - H N Liu
- Institut für Kernphysik, Technische Universität Darmstadt, 64289 Darmstadt, Germany
- Key Laboratory of Beam Technology of Ministry of Education, College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875, China
- Department of Physics, Royal Institute of Technology, SE-10691 Stockholm, Sweden
| | - A Obertelli
- Institut für Kernphysik, Technische Universität Darmstadt, 64289 Darmstadt, Germany
- IRFU, CEA, Université Paris-Saclay, F-91191 Gif-sur-Yvette, France
- RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - P Doornenbal
- RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - F Nowacki
- Université de Strasbourg, CNRS, IPHC UMR 7178, F-67000 Strasbourg, France
| | - K Ogata
- Department of Physics, Kyushu University, Fukuoka 819-0395, Japan
- Research Center for Nuclear Physics (RCNP), Osaka University, Ibaraki 567-0047, Japan
| | - A Poves
- Departamento de Fisica Teorica and IFT UAM-CSIC, Universidad Autonoma de Madrid, Spain
| | - K Yoshida
- Advanced Science Research Center, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195, Japan
| | - N L Achouri
- LPC Caen, Normandie Université, ENSICAEN, UNICAEN, CNRS/IN2P3, F-14000 Caen, France
| | - H Baba
- RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - F Browne
- RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - D Calvet
- IRFU, CEA, Université Paris-Saclay, F-91191 Gif-sur-Yvette, France
| | - F Château
- IRFU, CEA, Université Paris-Saclay, F-91191 Gif-sur-Yvette, France
| | - S Chen
- RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
- Department of Physics, The University of Hong Kong, Pokfulam, Hong Kong
- State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871, China
| | - N Chiga
- RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - A Corsi
- IRFU, CEA, Université Paris-Saclay, F-91191 Gif-sur-Yvette, France
| | - M L Cortés
- RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - A Delbart
- IRFU, CEA, Université Paris-Saclay, F-91191 Gif-sur-Yvette, France
| | - J-M Gheller
- IRFU, CEA, Université Paris-Saclay, F-91191 Gif-sur-Yvette, France
| | - A Giganon
- IRFU, CEA, Université Paris-Saclay, F-91191 Gif-sur-Yvette, France
| | - A Gillibert
- IRFU, CEA, Université Paris-Saclay, F-91191 Gif-sur-Yvette, France
| | - C Hilaire
- IRFU, CEA, Université Paris-Saclay, F-91191 Gif-sur-Yvette, France
| | - T Isobe
- RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - T Kobayashi
- Department of Physics, Tohoku University, Sendai 980-8578, Japan
| | - Y Kubota
- RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
- Center for Nuclear Study, University of Tokyo, RIKEN campus, Wako, Saitama 351-0198, Japan
| | - V Lapoux
- IRFU, CEA, Université Paris-Saclay, F-91191 Gif-sur-Yvette, France
| | - T Motobayashi
- RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - I Murray
- RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
- Université Paris-Saclay, CNRS/IN2P3, IJCLab, F-91405 Orsay cedex, France
| | - H Otsu
- RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - V Panin
- RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - N Paul
- IRFU, CEA, Université Paris-Saclay, F-91191 Gif-sur-Yvette, France
- Laboratoire Kastler Brossel, Sorbonne Université, CNRS, ENS, PSL Research University, Collège de France, Case 74, 4 Place Jussieu, 75005 Paris, France
| | - W Rodriguez
- RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
- Pontificia Universidad Javeriana, Facultad de Ciencias, Departamento de Física, Bogotá, Colombia
- Universidad Nacional de Colombia, Sede Bogotá, Facultad de Ciencias, Departamento de Física, Bogotá 111321, Colombia
| | - H Sakurai
- RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
- Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033, Japan
| | - M Sasano
- RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - D Steppenbeck
- RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - L Stuhl
- Center for Nuclear Study, University of Tokyo, RIKEN campus, Wako, Saitama 351-0198, Japan
- Institute for Nuclear Research, Atomki, P.O. Box 51, Debrecen H-4001, Hungary
- Institute for Basic Science, Daejeon 34126, Korea
| | - Y L Sun
- Institut für Kernphysik, Technische Universität Darmstadt, 64289 Darmstadt, Germany
- IRFU, CEA, Université Paris-Saclay, F-91191 Gif-sur-Yvette, France
| | - Y Togano
- RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
- Department of Physics, Rikkyo University, 3-34-1 Nishi-Ikebukuro, Toshima, Tokyo 172-8501, Japan
| | - T Uesaka
- RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - K Wimmer
- RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
- Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033, Japan
| | - K Yoneda
- RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - O Aktas
- Department of Physics, Royal Institute of Technology, SE-10691 Stockholm, Sweden
| | - T Aumann
- Institut für Kernphysik, Technische Universität Darmstadt, 64289 Darmstadt, Germany
- GSI Helmholtzzentrum für Schwerionenforschung GmbH, Planckstrasse 1, 64291 Darmstadt, Germany
| | - L X Chung
- Institute for Nuclear Science & Technology, VINATOM, 179 Hoang Quoc Viet, Cau Giay, Hanoi, Vietnam
| | - F Flavigny
- LPC Caen, Normandie Université, ENSICAEN, UNICAEN, CNRS/IN2P3, F-14000 Caen, France
- Université Paris-Saclay, CNRS/IN2P3, IJCLab, F-91405 Orsay cedex, France
| | - S Franchoo
- Université Paris-Saclay, CNRS/IN2P3, IJCLab, F-91405 Orsay cedex, France
| | - I Gasparic
- Institut für Kernphysik, Technische Universität Darmstadt, 64289 Darmstadt, Germany
- RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
- Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia
| | - R-B Gerst
- Institut für Kernphysik, Universität zu Köln, D-50937 Cologne, Germany
| | - J Gibelin
- LPC Caen, Normandie Université, ENSICAEN, UNICAEN, CNRS/IN2P3, F-14000 Caen, France
| | - K I Hahn
- Institute for Basic Science, Daejeon 34126, Korea
- Ewha Womans University, Seoul 03760, Korea
| | - D Kim
- RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
- Institute for Basic Science, Daejeon 34126, Korea
- Ewha Womans University, Seoul 03760, Korea
| | - Y Kondo
- Department of Physics, Tokyo Institute of Technology, 2-12-1 O-Okayama, Meguro, Tokyo, 152-8551, Japan
| | - P Koseoglou
- Institut für Kernphysik, Technische Universität Darmstadt, 64289 Darmstadt, Germany
- GSI Helmholtzzentrum für Schwerionenforschung GmbH, Planckstrasse 1, 64291 Darmstadt, Germany
| | - J Lee
- Department of Physics, The University of Hong Kong, Pokfulam, Hong Kong
| | - C Lehr
- Institut für Kernphysik, Technische Universität Darmstadt, 64289 Darmstadt, Germany
| | - P J Li
- Department of Physics, The University of Hong Kong, Pokfulam, Hong Kong
| | - B D Linh
- Institute for Nuclear Science & Technology, VINATOM, 179 Hoang Quoc Viet, Cau Giay, Hanoi, Vietnam
| | - T Lokotko
- Department of Physics, The University of Hong Kong, Pokfulam, Hong Kong
| | - M MacCormick
- Université Paris-Saclay, CNRS/IN2P3, IJCLab, F-91405 Orsay cedex, France
| | - K Moschner
- Institut für Kernphysik, Universität zu Köln, D-50937 Cologne, Germany
| | - T Nakamura
- Department of Physics, Tokyo Institute of Technology, 2-12-1 O-Okayama, Meguro, Tokyo, 152-8551, Japan
| | - S Y Park
- Institute for Basic Science, Daejeon 34126, Korea
- Ewha Womans University, Seoul 03760, Korea
| | - D Rossi
- Institut für Kernphysik, Technische Universität Darmstadt, 64289 Darmstadt, Germany
| | - E Sahin
- Department of Physics, University of Oslo, N-0316 Oslo, Norway
| | - P-A Söderström
- Institut für Kernphysik, Technische Universität Darmstadt, 64289 Darmstadt, Germany
| | - D Sohler
- Institute for Nuclear Research, Atomki, P.O. Box 51, Debrecen H-4001, Hungary
| | - S Takeuchi
- Department of Physics, Tokyo Institute of Technology, 2-12-1 O-Okayama, Meguro, Tokyo, 152-8551, Japan
| | - H Toernqvist
- Institut für Kernphysik, Technische Universität Darmstadt, 64289 Darmstadt, Germany
- GSI Helmholtzzentrum für Schwerionenforschung GmbH, Planckstrasse 1, 64291 Darmstadt, Germany
| | - V Vaquero
- Instituto de Estructura de la Materia, CSIC, E-28006 Madrid, Spain
| | - V Wagner
- Institut für Kernphysik, Technische Universität Darmstadt, 64289 Darmstadt, Germany
| | - S Wang
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China
| | - V Werner
- Institut für Kernphysik, Technische Universität Darmstadt, 64289 Darmstadt, Germany
- Helmholtz Forschungsakademie Hessen für FAIR (HFHF), GSI Helmholtzzentrum für Schwerionenforschung, Campus Darmstadt, 64289 Darmstadt, Germany
| | - X Xu
- Department of Physics, The University of Hong Kong, Pokfulam, Hong Kong
| | - H Yamada
- Department of Physics, Tokyo Institute of Technology, 2-12-1 O-Okayama, Meguro, Tokyo, 152-8551, Japan
| | - D Yan
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China
| | - Z Yang
- RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - M Yasuda
- Department of Physics, Tokyo Institute of Technology, 2-12-1 O-Okayama, Meguro, Tokyo, 152-8551, Japan
| | - L Zanetti
- Institut für Kernphysik, Technische Universität Darmstadt, 64289 Darmstadt, Germany
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2
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Michimasa S, Kobayashi M, Kiyokawa Y, Ota S, Yokoyama R, Nishimura D, Ahn DS, Baba H, Berg GPA, Dozono M, Fukuda N, Furuno T, Ideguchi E, Inabe N, Kawabata T, Kawase S, Kisamori K, Kobayashi K, Kubo T, Kubota Y, Lee CS, Matsushita M, Miya H, Mizukami A, Nagakura H, Oikawa H, Sakai H, Shimizu Y, Stolz A, Suzuki H, Takaki M, Takeda H, Takeuchi S, Tokieda H, Uesaka T, Yako K, Yamaguchi Y, Yanagisawa Y, Yoshida K, Shimoura S. Mapping of a New Deformation Region around ^{62}Ti. PHYSICAL REVIEW LETTERS 2020; 125:122501. [PMID: 33016755 DOI: 10.1103/physrevlett.125.122501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 06/12/2020] [Accepted: 07/21/2020] [Indexed: 06/11/2023]
Abstract
We performed the first direct mass measurements of neutron-rich scandium, titanium, and vanadium isotopes around the neutron number 40 at the RIKEN RI Beam Factory using the time-of-flight magnetic-rigidity technique. The atomic mass excesses of ^{58-60}Sc, ^{60-62}Ti, and ^{62-64}V were measured for the first time. The experimental results show that the two-neutron separation energies in the vicinity of ^{62}Ti increase compared to neighboring nuclei. This shows that the masses of Ti isotopes near N=40 are affected by the Jahn-Teller effect. Therefore, a development of Jahn-Teller stabilization appears below the Cr isotopes, and the systematics in Sc, Ti, and V isotopes suggest that ^{62}Ti is located close to the peak of the Jahn-Teller effect.
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Affiliation(s)
- S Michimasa
- Center for Nuclear Study, The University of Tokyo, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - M Kobayashi
- Center for Nuclear Study, The University of Tokyo, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Y Kiyokawa
- Center for Nuclear Study, The University of Tokyo, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - S Ota
- Center for Nuclear Study, The University of Tokyo, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - R Yokoyama
- Department of Physics and Astronomy, the University of Tennessee, Knoxville, Tennessee 37996, USA
| | - D Nishimura
- Center for Nuclear Study, The University of Tokyo, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
- Department of Natural Sciences, Tokyo City University, Tamazutsumi 1-28-1, Setagaya-ku, Tokyo 158-8557, Japan
| | - D S Ahn
- RIKEN Nishina Center for Accelerator-Based Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - H Baba
- RIKEN Nishina Center for Accelerator-Based Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - G P A Berg
- Department of Physics and Joint Institute for Nuclear Astrophysics, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - M Dozono
- Center for Nuclear Study, The University of Tokyo, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - N Fukuda
- RIKEN Nishina Center for Accelerator-Based Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - T Furuno
- Department of Physics, Kyoto University, Kitashirakawa-Oiwake, Sakyo, Kyoto 606-8502, Japan
| | - E Ideguchi
- Research Center for Nuclear Physics, Osaka University, 10-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan
| | - N Inabe
- RIKEN Nishina Center for Accelerator-Based Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - T Kawabata
- Department of Physics, Kyoto University, Kitashirakawa-Oiwake, Sakyo, Kyoto 606-8502, Japan
| | - S Kawase
- Department of Advanced Energy Engineering Science, Kyushu University, 6-1 Kasuga-koen, Kasuga, Fukuoka 816-8580, Japan
| | - K Kisamori
- Center for Nuclear Study, The University of Tokyo, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - K Kobayashi
- Department of Physics, Rikkyo University, Toshima, Tokyo 171-8501, Japan
| | - T Kubo
- Facility for Rare Isotope Beams, Michigan State University, 640 S Shaw Lane, East Lansing, Michigan 48824, USA
- National Superconducting Cyclotron Laboratory, Michigan State University, 640 S Shaw Lane, East Lansing, Michigan 48824, USA
| | - Y Kubota
- RIKEN Nishina Center for Accelerator-Based Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - C S Lee
- Center for Nuclear Study, The University of Tokyo, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - M Matsushita
- Center for Nuclear Study, The University of Tokyo, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - H Miya
- Center for Nuclear Study, The University of Tokyo, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - A Mizukami
- Department of Physics, Tokyo University of Science, Noda, Chiba 278-8510, Japan
| | - H Nagakura
- Department of Physics, Rikkyo University, Toshima, Tokyo 171-8501, Japan
| | - H Oikawa
- Department of Physics, Tokyo University of Science, Noda, Chiba 278-8510, Japan
| | - H Sakai
- RIKEN Nishina Center for Accelerator-Based Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Y Shimizu
- RIKEN Nishina Center for Accelerator-Based Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - A Stolz
- National Superconducting Cyclotron Laboratory, Michigan State University, 640 S Shaw Lane, East Lansing, Michigan 48824, USA
| | - H Suzuki
- RIKEN Nishina Center for Accelerator-Based Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - M Takaki
- Center for Nuclear Study, The University of Tokyo, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - H Takeda
- RIKEN Nishina Center for Accelerator-Based Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - S Takeuchi
- Department of Physics, Tokyo Institute of Technology, Meguro, Tokyo 152-8551, Japan
| | - H Tokieda
- Center for Nuclear Study, The University of Tokyo, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - T Uesaka
- RIKEN Nishina Center for Accelerator-Based Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - K Yako
- Center for Nuclear Study, The University of Tokyo, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Y Yamaguchi
- Center for Nuclear Study, The University of Tokyo, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Y Yanagisawa
- RIKEN Nishina Center for Accelerator-Based Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - K Yoshida
- RIKEN Nishina Center for Accelerator-Based Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - S Shimoura
- Center for Nuclear Study, The University of Tokyo, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
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3
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78Ni revealed as a doubly magic stronghold against nuclear deformation. Nature 2019; 569:53-58. [PMID: 31043730 DOI: 10.1038/s41586-019-1155-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Accepted: 03/15/2019] [Indexed: 11/08/2022]
Abstract
Nuclear magic numbers correspond to fully occupied energy shells of protons or neutrons inside atomic nuclei. Doubly magic nuclei, with magic numbers for both protons and neutrons, are spherical and extremely rare across the nuclear landscape. Although the sequence of magic numbers is well established for stable nuclei, experimental evidence has revealed modifications for nuclei with a large asymmetry between proton and neutron numbers. Here we provide a spectroscopic study of the doubly magic nucleus 78Ni, which contains fourteen neutrons more than the heaviest stable nickel isotope. We provide direct evidence of its doubly magic nature, which is also predicted by ab initio calculations based on chiral effective-field theory interactions and the quasi-particle random-phase approximation. Our results also indicate the breakdown of the neutron magic number 50 and proton magic number 28 beyond this stronghold, caused by a competing deformed structure. State-of-the-art phenomenological shell-model calculations reproduce this shape coexistence, predicting a rapid transition from spherical to deformed ground states, with 78Ni as the turning point.
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4
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Bagchi S, Kanungo R, Horiuchi W, Hagen G, Morris TD, Stroberg SR, Suzuki T, Ameil F, Atkinson J, Ayyad Y, Cortina-Gil D, Dillmann I, Estradé A, Evdokimov A, Farinon F, Geissel H, Guastalla G, Janik R, Kaur S, Knöbel R, Kurcewicz J, Litvinov Y, Marta M, Mostazo M, Mukha I, Nociforo C, Ong HJ, Pietri S, Prochazka A, Scheidenberger C, Sitar B, Strmen P, Takechi M, Tanaka J, Tanaka Y, Tanihata I, Terashima S, Vargas J, Weick H, Winfield JS. Measurement of proton-distribution radii of neutron-rich nitrogen isotopes. EPJ WEB OF CONFERENCES 2019. [DOI: 10.1051/epjconf/201922301003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Measurement of root-mean-square radii of proton distributions of 17–22N from charge-changing cross section shows the emergence of thick neutron skin towards the neutron-drip line. Signature of N = 14 shell gap has been found in nitrogen isotopes along with the emergence of neutron halo in 22N. The measured radii are in good agreement with the shell model calculations.
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5
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Michimasa S, Kobayashi M, Kiyokawa Y, Ota S, Ahn DS, Baba H, Berg GPA, Dozono M, Fukuda N, Furuno T, Ideguchi E, Inabe N, Kawabata T, Kawase S, Kisamori K, Kobayashi K, Kubo T, Kubota Y, Lee CS, Matsushita M, Miya H, Mizukami A, Nagakura H, Nishimura D, Oikawa H, Sakai H, Shimizu Y, Stolz A, Suzuki H, Takaki M, Takeda H, Takeuchi S, Tokieda H, Uesaka T, Yako K, Yamaguchi Y, Yanagisawa Y, Yokoyama R, Yoshida K, Shimoura S. Magic Nature of Neutrons in ^{54}Ca: First Mass Measurements of ^{55-57}Ca. PHYSICAL REVIEW LETTERS 2018; 121:022506. [PMID: 30085708 DOI: 10.1103/physrevlett.121.022506] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Revised: 04/21/2018] [Indexed: 06/08/2023]
Abstract
We perform the first direct mass measurements of neutron-rich calcium isotopes beyond neutron number 34 at the RIKEN Radioactive Isotope Beam Factory by using the time-of-flight magnetic-rigidity technique. The atomic mass excesses of ^{55-57}Ca are determined for the first time to be -18650(160), -13510(250), and -7370(990) keV, respectively. We examine the emergence of neutron magicity at N=34 based on the new atomic masses. The new masses provide experimental evidence for the appearance of a sizable energy gap between the neutron 2p_{1/2} and 1f_{5/2} orbitals in ^{54}Ca, comparable to the gap between the neutron 2p_{3/2} and 2p_{1/2} orbitals in ^{52}Ca. For the ^{56}Ca nucleus, an open-shell property in neutrons is suggested.
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Affiliation(s)
- S Michimasa
- Center for Nuclear Study, The University of Tokyo, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - M Kobayashi
- Center for Nuclear Study, The University of Tokyo, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Y Kiyokawa
- Center for Nuclear Study, The University of Tokyo, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - S Ota
- Center for Nuclear Study, The University of Tokyo, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - D S Ahn
- RIKEN Nishina Center for Accelerator-Based Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - H Baba
- RIKEN Nishina Center for Accelerator-Based Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - G P A Berg
- Department of Physics and Joint Institute for Nuclear Astrophysics, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - M Dozono
- Center for Nuclear Study, The University of Tokyo, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - N Fukuda
- RIKEN Nishina Center for Accelerator-Based Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - T Furuno
- Department of Physics, Kyoto University, Kitashirakawa-Oiwake, Sakyo, Kyoto 606-8502, Japan
| | - E Ideguchi
- Research Center for Nuclear Physics, Osaka University, 10-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan
| | - N Inabe
- RIKEN Nishina Center for Accelerator-Based Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - T Kawabata
- Department of Physics, Kyoto University, Kitashirakawa-Oiwake, Sakyo, Kyoto 606-8502, Japan
| | - S Kawase
- Department of Advanced Energy Engineering Sciences, Kyushu University, 6-1 Kasuga-koen, Kasuga, Fukuoka 816-8580, Japan
| | - K Kisamori
- Center for Nuclear Study, The University of Tokyo, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - K Kobayashi
- Department of Physics, Rikkyo University, Toshima, Tokyo 171-8501, Japan
| | - T Kubo
- Facility for Rare Isotope Beams, Michigan State University, 640 South Shaw Lane, East Lansing, Michigan 48824, USA
- National Superconducting Cyclotron Laboratory, Michigan State University, 640 South Shaw Lane, East Lansing, Michigan 48824, USA
| | - Y Kubota
- RIKEN Nishina Center for Accelerator-Based Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - C S Lee
- Center for Nuclear Study, The University of Tokyo, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
- RIKEN Nishina Center for Accelerator-Based Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - M Matsushita
- Center for Nuclear Study, The University of Tokyo, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - H Miya
- Center for Nuclear Study, The University of Tokyo, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - A Mizukami
- Department of Physics, Tokyo University of Science, Noda, Chiba 278-8510, Japan
| | - H Nagakura
- Department of Physics, Rikkyo University, Toshima, Tokyo 171-8501, Japan
| | - D Nishimura
- Department of Physics, Tokyo City University, Tamazutsumi 1-28-1, Setagaya-ku, Tokyo 158-8557, Japan
| | - H Oikawa
- Department of Physics, Tokyo University of Science, Noda, Chiba 278-8510, Japan
| | - H Sakai
- RIKEN Nishina Center for Accelerator-Based Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Y Shimizu
- RIKEN Nishina Center for Accelerator-Based Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - A Stolz
- National Superconducting Cyclotron Laboratory, Michigan State University, 640 South Shaw Lane, East Lansing, Michigan 48824, USA
| | - H Suzuki
- RIKEN Nishina Center for Accelerator-Based Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - M Takaki
- Center for Nuclear Study, The University of Tokyo, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - H Takeda
- RIKEN Nishina Center for Accelerator-Based Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - S Takeuchi
- Department of Physics, Tokyo Institute of Technology, Meguro, Tokyo 152-8551, Japan
| | - H Tokieda
- Center for Nuclear Study, The University of Tokyo, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - T Uesaka
- RIKEN Nishina Center for Accelerator-Based Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - K Yako
- Center for Nuclear Study, The University of Tokyo, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Y Yamaguchi
- Center for Nuclear Study, The University of Tokyo, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Y Yanagisawa
- RIKEN Nishina Center for Accelerator-Based Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - R Yokoyama
- Department of Physics and Astronomy, The University of Tennessee, Knoxville, Tennessee 37996, USA
| | - K Yoshida
- RIKEN Nishina Center for Accelerator-Based Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - S Shimoura
- Center for Nuclear Study, The University of Tokyo, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
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6
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Zhao PW, Itagaki N, Meng J. Rod-shaped Nuclei at Extreme Spin and Isospin. PHYSICAL REVIEW LETTERS 2015; 115:022501. [PMID: 26207464 DOI: 10.1103/physrevlett.115.022501] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Indexed: 05/28/2023]
Abstract
The anomalous rod shape in carbon isotopes has been investigated in the framework of the cranking covariant density functional theory, and two mechanisms to stabilize such a novel shape with respect to the bending motion, extreme spin, and isospin are simultaneously discussed for the first time in a self-consistent and microscopic way. By adding valence neutrons and rotating the system, we have found the mechanism stabilizing the rod shape; i.e., the σ orbitals (parallel to the symmetry axis) of the valence neutrons, important for the rod shape, are lowered by the rotation due to the Coriolis term. The spin and isospin effects enhance the stability of the rod-shaped configuration. This provides a strong hint that a rod shape could be realized in nuclei towards extreme spin and isospin.
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Affiliation(s)
- P W Zhao
- Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502, Japan
- Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
- State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871, China
| | - N Itagaki
- Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502, Japan
| | - J Meng
- State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871, China
- School of Physics and Nuclear Energy Engineering, Beihang University, Beijing 100191, China
- Department of Physics, University of Stellenbosch, Stellenbosch 7602, South Africa
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7
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8
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Takeuchi S, Matsushita M, Aoi N, Doornenbal P, Li K, Motobayashi T, Scheit H, Steppenbeck D, Wang H, Baba H, Bazin D, Càceres L, Crawford H, Fallon P, Gernhäuser R, Gibelin J, Go S, Grévy S, Hinke C, Hoffman CR, Hughes R, Ideguchi E, Jenkins D, Kobayashi N, Kondo Y, Krücken R, Le Bleis T, Lee J, Lee G, Matta A, Michimasa S, Nakamura T, Ota S, Petri M, Sako T, Sakurai H, Shimoura S, Steiger K, Takahashi K, Takechi M, Togano Y, Winkler R, Yoneda K. Well developed deformation in 42Si. PHYSICAL REVIEW LETTERS 2012; 109:182501. [PMID: 23215274 DOI: 10.1103/physrevlett.109.182501] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2012] [Revised: 09/19/2012] [Indexed: 06/01/2023]
Abstract
Excited states in (38,40,42) Si nuclei have been studied via in-beam γ-ray spectroscopy with multinucleon removal reactions. Intense radioactive beams of ^{40}S and (44)S provided at the new facility of the RIKEN Radioactive Isotope Beam Factory enabled γ-γ coincidence measurements. A prominent γ line observed with an energy of 742(8) keV in (42) Si confirms the 2(+) state reported in an earlier study. Among the γ lines observed in coincidence with the 2^{+} → 0+ transition, the most probable candidate for the transition from the yrast 4(+) state was identified, leading to a 4(1)+) energy of 2173(14) keV. The energy ratio of 2.93(5) between the 2(1)+ and 4(1)(+) states indicates well-developed deformation in (42) Si at N = 28 and Z = 14. Also for 38,40)Si energy ratios with values of 2.09(5) and 2.56(5) were obtained. Together with the ratio for (42)Si, the results show a rapid deformation development of Si isotopes from N = 24 to N = 28.
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Affiliation(s)
- S Takeuchi
- RIKEN Nishina Center, Wako, Saitama 351-0198, Japan
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9
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Krieger A, Blaum K, Bissell ML, Frömmgen N, Geppert C, Hammen M, Kreim K, Kowalska M, Krämer J, Neff T, Neugart R, Neyens G, Nörtershäuser W, Novotny C, Sánchez R, Yordanov DT. Nuclear charge radius of 12Be. PHYSICAL REVIEW LETTERS 2012; 108:142501. [PMID: 22540787 DOI: 10.1103/physrevlett.108.142501] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2011] [Indexed: 05/31/2023]
Abstract
The nuclear charge radius of (12)Be was precisely determined using the technique of collinear laser spectroscopy on the 2s(1/2)→2p(1/2,3/2) transition in the Be(+) ion. The mean square charge radius increases from (10)Be to (12)Be by δ<r(c)(2)>(10,12)=0.69(5) fm(2) compared to δ<r(c)(2)>(10,11)=0.49(5) fm(2) for the one-neutron halo isotope ^{11}Be. Calculations in the fermionic molecular dynamics approach show a strong sensitivity of the charge radius to the structure of ^{12}Be. The experimental charge radius is consistent with a breakdown of the N=8 shell closure.
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Affiliation(s)
- A Krieger
- Institut für Kernchemie, Johannes Gutenberg-Universität Mainz, D-55128 Mainz, Germany
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10
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Meharchand R, Zegers RGT, Brown BA, Austin SM, Baugher T, Bazin D, Deaven J, Gade A, Grinyer GF, Guess CJ, Howard ME, Iwasaki H, McDaniel S, Meierbachtol K, Perdikakis G, Pereira J, Prinke AM, Ratkiewicz A, Signoracci A, Stroberg S, Valdez L, Voss P, Walsh KA, Weisshaar D, Winkler R. Probing configuration mixing in 12Be with Gamow-Teller transition strengths. PHYSICAL REVIEW LETTERS 2012; 108:122501. [PMID: 22540576 DOI: 10.1103/physrevlett.108.122501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2011] [Indexed: 05/31/2023]
Abstract
We present a novel technique for studying the quenching of shell gaps in exotic isotopes. The method is based on extracting Gamow-Teller (ΔL=0, ΔS=1) transition strengths [B(GT)] to low-lying states from charge-exchange reactions at intermediate beam energies. These Gamow-Teller strengths are very sensitive to configuration mixing between cross-shell orbitals, and this technique thus provides an important complement to other tools currently used to study cross-shell mixing. This work focuses on the N=8 shell gap. We populated the ground and 2.24 MeV 0+ states in 12Be using the 12B(1+) (7Li, 7Be) reaction at 80 MeV/u in inverse kinematics. Using the ground-state B(GT) value from β-decay measurements (0.184±0.007) as a calibration, the B(GT) for the transition to the second 0+ state was determined to be 0.214±0.051. Comparing the extracted Gamow-Teller strengths with shell-model calculations, it was determined that the wave functions of the first and second 0+ states in 12Be are composed of 25±5% and 60±5% (0s)4(0p)8 configurations, respectively.
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Affiliation(s)
- R Meharchand
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824-1321, USA.
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11
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Baumann T, Spyrou A, Thoennessen M. Nuclear structure experiments along the neutron drip line. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2012; 75:036301. [PMID: 22790419 DOI: 10.1088/0034-4885/75/3/036301] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Invariant mass measurements and breakup reactions of neutron-rich nuclei have been instrumental in the study of nuclear structure effects at the limit of nuclear existence. The measurements of neutron-unbound states rely on the detection of neutrons in coincidence with fragments at energies between 100 and 1000 MeV/u. Charged particle and γ-ray coincidence measurements yield additional information. The production and detection methods for these experiments and examples of results in light nuclei are presented. Future opportunities with new facilities and the development of new detectors are described.
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Affiliation(s)
- T Baumann
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824-1321, USA.
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12
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Grinyer GF, Bazin D, Gade A, Tostevin JA, Adrich P, Bowen MD, Brown BA, Campbell CM, Cook JM, Glasmacher T, McDaniel S, Navrátil P, Obertelli A, Quaglioni S, Siwek K, Terry JR, Weisshaar D, Wiringa RB. Knockout reactions from p-shell nuclei: tests of ab initio structure models. PHYSICAL REVIEW LETTERS 2011; 106:162502. [PMID: 21599362 DOI: 10.1103/physrevlett.106.162502] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Indexed: 05/30/2023]
Abstract
Absolute cross sections have been determined following single neutron knockout reactions from 10Be and 10C at intermediate energy. Nucleon density distributions and bound-state wave function overlaps obtained from both variational Monte Carlo (VMC) and no core shell model (NCSM) ab initio calculations have been incorporated into the theoretical description of knockout reactions. Comparison to experimental cross sections demonstrates that the VMC approach, with the inclusion of 3-body forces, provides the best overall agreement while the NCSM and conventional shell-model calculations both overpredict the cross sections by 20% to 30% for 10Be and by 40% to 50% for 10C, respectively. This study gains new insight into the importance of 3-body forces and continuum effects in light nuclei and provides a sensitive technique to assess the accuracy of ab initio calculations for describing these effects.
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Affiliation(s)
- G F Grinyer
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA.
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13
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Suzuki D, Iwasaki H, Beaumel D, Nalpas L, Pollacco E, Assié M, Baba H, Blumenfeld Y, De Séréville N, Drouart A, Franchoo S, Gillibert A, Guillot J, Hammache F, Keeley N, Lapoux V, Maréchal F, Michimasa S, Mougeot X, Mukha I, Okamura H, Otsu H, Ramus A, Roussel-Chomaz P, Sakurai H, Scarpaci JA, Sorlin O, Stefan I, Takechi M. Breakdown of the Z=8 shell closure in unbound 12O and its mirror symmetry. PHYSICAL REVIEW LETTERS 2009; 103:152503. [PMID: 19905630 DOI: 10.1103/physrevlett.103.152503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2009] [Indexed: 05/28/2023]
Abstract
An excited state in the proton-rich unbound nucleus 12O was identified at 1.8(4) MeV via missing-mass spectroscopy with the 14O(p,t) reaction at 51 AMeV. The spin-parity of the state was determined to be 0+ or 2+ by comparing the measured differential cross sections with distorted-wave calculations. The lowered location of the excited state in 12O indicates the breakdown of the major shell closure at Z=8 near the proton drip line. This demonstrates the persistence of mirror symmetry in the disappearance of the magic number 8 between 12O and its mirror partner 12Be.
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Affiliation(s)
- D Suzuki
- Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033, Japan
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14
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Iwasaki H, Dewald A, Fransen C, Gelberg A, Hackstein M, Jolie J, Petkov P, Pissulla T, Rother W, Zell KO. Low-lying neutron intruder state in 13B and the fading of the N = 8 shell closure. PHYSICAL REVIEW LETTERS 2009; 102:202502. [PMID: 19519024 DOI: 10.1103/physrevlett.102.202502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2009] [Revised: 04/28/2009] [Indexed: 05/27/2023]
Abstract
A lifetime measurement of the excited states in the neutron-rich isotope (13)B has been performed using the (7)Li((7)Li,p)(13)B reaction. An anomalously long mean lifetime of 1.3(3) ps was found for the excited state at 3.53 MeV, giving the upper limits of the transition strengths to the ground state: B(M1) = 7.2 x 10;{-4} Weisskopf unit (W.u.) and B(E2) = 0.81 W.u.. The hindered transition strengths indicate significant intruder configurations for the excited state, coexisting with the normal ground state. The data are well explained by recent shell-model calculations, which suggest J;{pi} = 3/2;{-} for the 3.53-MeV state with the dominant intruder (nu2p2h) configuration.
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Affiliation(s)
- H Iwasaki
- Institut für Kernphysik, Universität zu Köln, D-50937 Köln, Germany
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15
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Aoi N, Takeshita E, Suzuki H, Takeuchi S, Ota S, Baba H, Bishop S, Fukui T, Hashimoto Y, Ong HJ, Ideguchi E, Ieki K, Imai N, Ishihara M, Iwasaki H, Kanno S, Kondo Y, Kubo T, Kurita K, Kusaka K, Minemura T, Motobayashi T, Nakabayashi T, Nakamura T, Nakao T, Niikura M, Okumura T, Ohnishi TK, Sakurai H, Shimoura S, Sugo R, Suzuki D, Suzuki MK, Tamaki M, Tanaka K, Togano Y, Yamada K. Development of large deformation in 62Cr. PHYSICAL REVIEW LETTERS 2009; 102:012502. [PMID: 19257184 DOI: 10.1103/physrevlett.102.012502] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2008] [Indexed: 05/27/2023]
Abstract
The structure of neutron-rich isotopes 60Cr and 62Cr was studied via proton inelastic scattering in inverse kinematics. The deformation lengths (delta) for 60Cr and 62Cr were extracted as 1.12(16) and 1.36(14) fm, respectively, providing evidence for enhanced collectivity in these nuclei. An excited state at 1180(10) keV in 62Cr was identified for the first time. We adopted 4;{+} as its spin and parity, leading to the rapid increase of the Ex(4;{+})/E_{x}(2;{+}) ratio, which indicates the development of large deformation in 62Cr near N=40. Importance of the admixture of the gd-shell component above N=40 is also discussed by comparing with a modern shell model calculation.
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Affiliation(s)
- N Aoi
- RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
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16
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Pain SD, Catford WN, Orr NA, Angélique JC, Ashwood NI, Bouchat V, Clarke NM, Curtis N, Freer M, Fulton BR, Hanappe F, Labiche M, Lecouey JL, Lemmon RC, Mahboub D, Ninane A, Normand G, Soić N, Stuttge L, Timis CN, Tostevin JA, Winfield JS, Ziman V. Structure of 12Be: intruder d-wave strength at N=8. PHYSICAL REVIEW LETTERS 2006; 96:032502. [PMID: 16486692 DOI: 10.1103/physrevlett.96.032502] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2005] [Indexed: 05/06/2023]
Abstract
The breaking of the N=8 shell-model magic number in the 12Be ground state has been determined to include significant occupancy of the intruder d-wave orbital. This is in marked contrast with all other N=8 isotones, both more and less exotic than 12Be. The occupancies of the [FORMULA: SEE TEXT]orbital and the [FORMULA: SEE TEXT], intruder orbital were deduced from a measurement of neutron removal from a high-energy 12Be beam leading to bound and unbound states in 11Be.
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Affiliation(s)
- S D Pain
- Department of Physics, University of Surrey, Guildford, GU2 7XH, United Kingdom
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17
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Alamanos N, Gillibert A. Selected Topics in Reaction Studies with Exotic Nuclei. THE EUROSCHOOL LECTURES ON PHYSICS WITH EXOTIC BEAMS, VOL. I 2004. [DOI: 10.1007/978-3-540-44490-9_9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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18
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Grigorenko LV, Mukha IG, Thompson IJ, Zhukov MV. Two-proton widths of 12O, 16Ne, and three-body mechanism of Thomas-Ehrman shift. PHYSICAL REVIEW LETTERS 2002; 88:042502. [PMID: 11801114 DOI: 10.1103/physrevlett.88.042502] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2001] [Indexed: 05/23/2023]
Abstract
Two-proton decays of 12O and 16Ne ground states are studied in a three-body model. We have found that the two-proton widths for the states should be much less than the existing experimental values (about 10 times for 12O and about 100 times for 16Ne). We also have found that the structure of these states differs significantly from the mirror isobaric analog states (IAS): breaking of isobaric symmetry is at the level of tens of percents. Together with a corresponding decrease of the Coulomb energy, this effect can be considered as a three-body mechanism of the Thomas-Ehrman shift.
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Affiliation(s)
- L V Grigorenko
- Department of Physics, University of Surrey, Guildford GU2 7XH, United Kingdom
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19
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Labiche M, Orr NA, Marqués FM, Angélique JC, Axelsson L, Benoit B, Bergmann UC, Borge MJ, Catford WN, Chappell SP, Clarke NM, Costa G, Curtis N, D'Arrigo A, de Góes Brennand E, Dorvaux O, Fazio G, Freer M, Fulton BR, Giardina G, Grévy S, Guillemaud-Mueller D, Hanappe F, Heusch B, Jones KL, Jonson B, Le Brun C, Leenhardt S, Lewitowicz M, Lopez MJ, Markenroth K, Mueller AC, Nilsson T, Ninane A, Nyman G, de Oliveira F, Piqueras I, Riisager K, Saint Laurent MG, Sarazin F, Singer SM, Sorlin O, Stuttgé L. Halo structure of (14)Be. PHYSICAL REVIEW LETTERS 2001; 86:600-603. [PMID: 11177891 DOI: 10.1103/physrevlett.86.600] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2000] [Indexed: 05/23/2023]
Abstract
The two-neutron halo nucleus (14)Be has been investigated in a kinematically complete measurement of the fragments ((12)Be and neutrons) produced in dissociation at 35 MeV/nucleon on C and Pb targets. Two-neutron removal cross sections, neutron angular distributions, and invariant mass spectra were measured, and the contributions from electromagnetic dissociation (EMD) were deduced. Comparison with three-body model calculations suggests that the halo wave function contains a large nu(2s(1/2))(2) admixture. The EMD invariant mass spectrum exhibited enhanced strength near threshold consistent with a nonresonant soft-dipole excitation.
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Affiliation(s)
- M Labiche
- Laboratoire de Physique Corpusculaire, ISMRA et Université de Caen, France
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