1
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Gray TJ, Allmond JM, Xu Z, King TT, Lubna RS, Crawford HL, Tripathi V, Crider BP, Grzywacz R, Liddick SN, Macchiavelli AO, Miyagi T, Poves A, Andalib A, Argo E, Benetti C, Bhattacharya S, Campbell CM, Carpenter MP, Chan J, Chester A, Christie J, Clark BR, Cox I, Doetsch AA, Dopfer J, Duarte JG, Fallon P, Frotscher A, Gaballah T, Harke JT, Heideman J, Huegen H, Holt JD, Jain R, Kitamura N, Kolos K, Kondev FG, Laminack A, Longfellow B, Luitel S, Madurga M, Mahajan R, Mogannam MJ, Morse C, Neupane S, Nowicki A, Ogunbeku TH, Ong WJ, Porzio C, Prokop CJ, Rasco BC, Ronning EK, Rubino E, Ruland TJ, Rykaczewski KP, Schaedig L, Seweryniak D, Siegl K, Singh M, Stuchbery AE, Tabor SL, Tang TL, Wheeler T, Winger JA, Wood JL. Microsecond Isomer at the N=20 Island of Shape Inversion Observed at FRIB. PHYSICAL REVIEW LETTERS 2023; 130:242501. [PMID: 37390416 DOI: 10.1103/physrevlett.130.242501] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Accepted: 04/26/2023] [Indexed: 07/02/2023]
Abstract
Excited-state spectroscopy from the first experiment at the Facility for Rare Isotope Beams (FRIB) is reported. A 24(2)-μs isomer was observed with the FRIB Decay Station initiator (FDSi) through a cascade of 224- and 401-keV γ rays in coincidence with ^{32}Na nuclei. This is the only known microsecond isomer (1 μs≤T_{1/2}<1 ms) in the region. This nucleus is at the heart of the N=20 island of shape inversion and is at the crossroads of the spherical shell-model, deformed shell-model, and ab initio theories. It can be represented as the coupling of a proton hole and neutron particle to ^{32}Mg, ^{32}Mg+π^{-1}+ν^{+1}. This odd-odd coupling and isomer formation provides a sensitive measure of the underlying shape degrees of freedom of ^{32}Mg, where the onset of spherical-to-deformed shape inversion begins with a low-lying deformed 2^{+} state at 885 keV and a low-lying shape-coexisting 0_{2}^{+} state at 1058 keV. We suggest two possible explanations for the 625-keV isomer in ^{32}Na: a 6^{-} spherical shape isomer that decays by E2 or a 0^{+} deformed spin isomer that decays by M2. The present results and calculations are most consistent with the latter, indicating that the low-lying states are dominated by deformation.
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Affiliation(s)
- T J Gray
- Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - J M Allmond
- Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Z Xu
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37966, USA
| | - T T King
- Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - R S Lubna
- Facility for Rare Isotope Beams, Michigan State University, East Lansing, Michigan 48824, USA
| | - H L Crawford
- Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - V Tripathi
- Department of Physics, Florida State University, Tallahassee, Florida 32306, USA
| | - B P Crider
- Department of Physics and Astronomy, Mississippi State University, Mississippi State, Mississippi 39762, USA
| | - R Grzywacz
- Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37966, USA
| | - S N Liddick
- Facility for Rare Isotope Beams, Michigan State University, East Lansing, Michigan 48824, USA
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA
| | - A O Macchiavelli
- Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - T Miyagi
- Department of Physics, Technische Universität Darmstadt, Darmstadt, Germany
- ExtreMe Matter Institute EMMI, GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt, Germany
| | - A Poves
- Departamento de Fìsica Teórica and IFT-UAM/CSIC, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| | - A Andalib
- Facility for Rare Isotope Beams, Michigan State University, East Lansing, Michigan 48824, USA
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
| | - E Argo
- Facility for Rare Isotope Beams, Michigan State University, East Lansing, Michigan 48824, USA
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
| | - C Benetti
- Department of Physics, Florida State University, Tallahassee, Florida 32306, USA
| | - S Bhattacharya
- Department of Physics, Florida State University, Tallahassee, Florida 32306, USA
| | - C M Campbell
- Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - M P Carpenter
- Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - J Chan
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37966, USA
| | - A Chester
- Facility for Rare Isotope Beams, Michigan State University, East Lansing, Michigan 48824, USA
| | - J Christie
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37966, USA
| | - B R Clark
- Department of Physics and Astronomy, Mississippi State University, Mississippi State, Mississippi 39762, USA
| | - I Cox
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37966, USA
| | - A A Doetsch
- Facility for Rare Isotope Beams, Michigan State University, East Lansing, Michigan 48824, USA
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
| | - J Dopfer
- Facility for Rare Isotope Beams, Michigan State University, East Lansing, Michigan 48824, USA
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
| | - J G Duarte
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - P Fallon
- Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - A Frotscher
- Department of Physics and Astronomy, Mississippi State University, Mississippi State, Mississippi 39762, USA
| | - T Gaballah
- Department of Physics and Astronomy, Mississippi State University, Mississippi State, Mississippi 39762, USA
| | - J T Harke
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - J Heideman
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37966, USA
| | - H Huegen
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37966, USA
| | - J D Holt
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada
- Department of Physics, McGill University, Montréal, Quebec City H3A 2T8, Canada
| | - R Jain
- Facility for Rare Isotope Beams, Michigan State University, East Lansing, Michigan 48824, USA
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
| | - N Kitamura
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37966, USA
| | - K Kolos
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - F G Kondev
- Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - A Laminack
- Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - B Longfellow
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - S Luitel
- Department of Physics and Astronomy, Mississippi State University, Mississippi State, Mississippi 39762, USA
| | - M Madurga
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37966, USA
| | - R Mahajan
- Facility for Rare Isotope Beams, Michigan State University, East Lansing, Michigan 48824, USA
| | - M J Mogannam
- Facility for Rare Isotope Beams, Michigan State University, East Lansing, Michigan 48824, USA
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA
| | - C Morse
- National Nuclear Data Center, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - S Neupane
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37966, USA
| | - A Nowicki
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37966, USA
| | - T H Ogunbeku
- Facility for Rare Isotope Beams, Michigan State University, East Lansing, Michigan 48824, USA
- Department of Physics and Astronomy, Mississippi State University, Mississippi State, Mississippi 39762, USA
| | - W-J Ong
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - C Porzio
- Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - C J Prokop
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - B C Rasco
- Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - E K Ronning
- Facility for Rare Isotope Beams, Michigan State University, East Lansing, Michigan 48824, USA
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA
| | - E Rubino
- Facility for Rare Isotope Beams, Michigan State University, East Lansing, Michigan 48824, USA
| | - T J Ruland
- Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803, USA
| | - K P Rykaczewski
- Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - L Schaedig
- Facility for Rare Isotope Beams, Michigan State University, East Lansing, Michigan 48824, USA
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
| | - D Seweryniak
- Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - K Siegl
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37966, USA
| | - M Singh
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37966, USA
| | - A E Stuchbery
- Department of Nuclear Physics and Accelerator Applications, Research School of Physics, Australian National University, Canberra, Australian Capital Territory, 2601, Australia
| | - S L Tabor
- Department of Physics, Florida State University, Tallahassee, Florida 32306, USA
| | - T L Tang
- Department of Physics, Florida State University, Tallahassee, Florida 32306, USA
| | - T Wheeler
- Facility for Rare Isotope Beams, Michigan State University, East Lansing, Michigan 48824, USA
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
| | - J A Winger
- Department of Physics and Astronomy, Mississippi State University, Mississippi State, Mississippi 39762, USA
| | - J L Wood
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332-0430, USA
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2
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Ahn DS, Amano J, Baba H, Fukuda N, Geissel H, Inabe N, Ishikawa S, Iwasa N, Komatsubara T, Kubo T, Kusaka K, Morrissey DJ, Nakamura T, Ohtake M, Otsu H, Sakakibara T, Sato H, Sherrill BM, Shimizu Y, Sumikama T, Suzuki H, Takeda H, Tarasov OB, Ueno H, Yanagisawa Y, Yoshida K. Discovery of ^{39}Na. PHYSICAL REVIEW LETTERS 2022; 129:212502. [PMID: 36461972 DOI: 10.1103/physrevlett.129.212502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 09/08/2022] [Accepted: 09/14/2022] [Indexed: 06/17/2023]
Abstract
The new isotope ^{39}Na, the most neutron-rich sodium nucleus observed so far, was discovered at the RIKEN Nishina Center Radioactive Isotope Beam Factory using the projectile fragmentation of an intense ^{48}Ca beam at 345 MeV/nucleon on a beryllium target. Projectile fragments were separated and identified in flight with the large-acceptance two-stage separator BigRIPS. Nine ^{39}Na events have been unambiguously observed in this work and clearly establish the particle stability of ^{39}Na. Furthermore, the lack of observation of ^{35,36}Ne isotopes in this experiment significantly improves the overall confidence that ^{34}Ne is the neutron dripline nucleus of neon. These results provide new key information to understand nuclear binding and nuclear structure under extremely neutron-rich conditions. The newly established stability of ^{39}Na has a significant impact on nuclear models and theories predicting the neutron dripline and also provides a key to understanding the nuclear shell property of ^{39}Na at the neutron number N=28, which is normally a magic number.
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Affiliation(s)
- D S Ahn
- RIKEN Nishina Center for Accelerator-Based Science, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - J Amano
- Department of Physics, Rikkyo University, 3-34-1 Nishi-Ikebukuro, Toshima, Tokyo 171-8501, Japan
| | - H Baba
- RIKEN Nishina Center for Accelerator-Based Science, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - N Fukuda
- RIKEN Nishina Center for Accelerator-Based Science, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - H Geissel
- GSI, Helmholtzzentrum für Schwerionenforschung GmbH, Planckstraße 1, 64291 Darmstadt, Germany
| | - N Inabe
- RIKEN Nishina Center for Accelerator-Based Science, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - S Ishikawa
- Department of Physics, Tohoku University, 6-3, Aramaki Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8578, Japan
| | - N Iwasa
- Department of Physics, Tohoku University, 6-3, Aramaki Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8578, Japan
| | - T Komatsubara
- RIKEN Nishina Center for Accelerator-Based Science, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - T Kubo
- RIKEN Nishina Center for Accelerator-Based Science, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - K Kusaka
- RIKEN Nishina Center for Accelerator-Based Science, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - D J Morrissey
- National Superconducting Cyclotron Laboratory, Michigan State University, 640 South Shaw Lane, East Lansing, Michigan 48824, USA
| | - T Nakamura
- Department of Physics, Tokyo Institute of Technology, 2-12-1 O-Okayama, Meguro, Tokyo 152-8551, Japan
| | - M Ohtake
- RIKEN Nishina Center for Accelerator-Based Science, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - H Otsu
- RIKEN Nishina Center for Accelerator-Based Science, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - T Sakakibara
- Department of Physics, Tohoku University, 6-3, Aramaki Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8578, Japan
| | - H Sato
- RIKEN Nishina Center for Accelerator-Based Science, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - B M Sherrill
- National Superconducting Cyclotron Laboratory, Michigan State University, 640 South Shaw Lane, East Lansing, Michigan 48824, USA
| | - Y Shimizu
- RIKEN Nishina Center for Accelerator-Based Science, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - T Sumikama
- RIKEN Nishina Center for Accelerator-Based Science, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - H Suzuki
- RIKEN Nishina Center for Accelerator-Based Science, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - H Takeda
- RIKEN Nishina Center for Accelerator-Based Science, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - O B Tarasov
- National Superconducting Cyclotron Laboratory, Michigan State University, 640 South Shaw Lane, East Lansing, Michigan 48824, USA
| | - H Ueno
- RIKEN Nishina Center for Accelerator-Based Science, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Y Yanagisawa
- RIKEN Nishina Center for Accelerator-Based Science, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - K Yoshida
- RIKEN Nishina Center for Accelerator-Based Science, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
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3
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The impact of nuclear shape on the emergence of the neutron dripline. Nature 2020; 587:66-71. [PMID: 33149291 DOI: 10.1038/s41586-020-2848-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Accepted: 09/03/2020] [Indexed: 11/08/2022]
Abstract
Atomic nuclei are composed of a certain number of protons Z and neutrons N. A natural question is how large Z and N can be. The study of superheavy elements explores the large Z limit1,2, and we are still looking for a comprehensive theoretical explanation of the largest possible N for a given Z-the existence limit for the neutron-rich isotopes of a given atomic species, known as the neutron dripline3. The neutron dripline of oxygen (Z = 8) can be understood theoretically as the result of single nucleons filling single-particle orbits confined by a mean potential, and experiments confirm this interpretation. However, recent experiments on heavier elements are at odds with this description. Here we show that the neutron dripline from fluorine (Z = 9) to magnesium (Z = 12) can be predicted using a mechanism that goes beyond the single-particle picture: as the number of neutrons increases, the nuclear shape assumes an increasingly ellipsoidal deformation, leading to a higher binding energy. The saturation of this effect (when the nucleus cannot be further deformed) yields the neutron dripline: beyond this maximum N, the isotope is unbound and further neutrons 'drip' out when added. Our calculations are based on a recently developed effective nucleon-nucleon interaction4, for which large-scale eigenvalue problems are solved using configuration-interaction simulations. The results obtained show good agreement with experiments, even for excitation energies of low-lying states, up to the nucleus of magnesium-40 (which has 28 neutrons). The proposed mechanism for the formation of the neutron dripline has the potential to stimulate further thinking in the field towards explaining nucleosynthesis with neutron-rich nuclei.
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4
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Bagchi S, Kanungo R, Tanaka YK, Geissel H, Doornenbal P, Horiuchi W, Hagen G, Suzuki T, Tsunoda N, Ahn DS, Baba H, Behr K, Browne F, Chen S, Cortés ML, Estradé A, Fukuda N, Holl M, Itahashi K, Iwasa N, Jansen GR, Jiang WG, Kaur S, Macchiavelli AO, Matsumoto SY, Momiyama S, Murray I, Nakamura T, Novario SJ, Ong HJ, Otsuka T, Papenbrock T, Paschalis S, Prochazka A, Scheidenberger C, Schrock P, Shimizu Y, Steppenbeck D, Sakurai H, Suzuki D, Suzuki H, Takechi M, Takeda H, Takeuchi S, Taniuchi R, Wimmer K, Yoshida K. Two-Neutron Halo is Unveiled in ^{29}F. PHYSICAL REVIEW LETTERS 2020; 124:222504. [PMID: 32567915 DOI: 10.1103/physrevlett.124.222504] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 04/17/2020] [Accepted: 05/08/2020] [Indexed: 06/11/2023]
Abstract
We report the measurement of reaction cross sections (σ_{R}^{ex}) of ^{27,29}F with a carbon target at RIKEN. The unexpectedly large σ_{R}^{ex} and derived matter radius identify ^{29}F as the heaviest two-neutron Borromean halo to date. The halo is attributed to neutrons occupying the 2p_{3/2} orbital, thereby vanishing the shell closure associated with the neutron number N=20. The results are explained by state-of-the-art shell model calculations. Coupled-cluster computations based on effective field theories of the strong nuclear force describe the matter radius of ^{27}F but are challenged for ^{29}F.
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Affiliation(s)
- S Bagchi
- Astronomy and Physics Department, Saint Mary's University, Halifax, Nova Scotia B3H 3C3, Canada
- GSI Helmholtzzentrum für Schwerionenforschung GmbH, D-64291 Darmstadt, Germany
- Justus-Liebig University, 35392 Giessen, Germany
| | - R Kanungo
- Astronomy and Physics Department, Saint Mary's University, Halifax, Nova Scotia B3H 3C3, Canada
- TRIUMF, Vancouver, British Columbia V6T 2A3, Canada
| | - Y K Tanaka
- Astronomy and Physics Department, Saint Mary's University, Halifax, Nova Scotia B3H 3C3, Canada
- GSI Helmholtzzentrum für Schwerionenforschung GmbH, D-64291 Darmstadt, Germany
- Justus-Liebig University, 35392 Giessen, Germany
| | - H Geissel
- GSI Helmholtzzentrum für Schwerionenforschung GmbH, D-64291 Darmstadt, Germany
- Justus-Liebig University, 35392 Giessen, Germany
| | - P Doornenbal
- RIKEN Nishina Center, Wako, Saitama 351-0198, Japan
| | - W Horiuchi
- Department of Physics, Hokkaido University, Sapporo 060-0810, Japan
| | - G Hagen
- Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - T Suzuki
- Department of Physics, Nihon University, Setagaya-ku, Tokyo 156-8550, Japan
| | - N Tsunoda
- Center for Nuclear Study, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - D S Ahn
- RIKEN Nishina Center, Wako, Saitama 351-0198, Japan
| | - H Baba
- RIKEN Nishina Center, Wako, Saitama 351-0198, Japan
| | - K Behr
- GSI Helmholtzzentrum für Schwerionenforschung GmbH, D-64291 Darmstadt, Germany
| | - F Browne
- RIKEN Nishina Center, Wako, Saitama 351-0198, Japan
| | - S Chen
- RIKEN Nishina Center, Wako, Saitama 351-0198, Japan
| | - M L Cortés
- RIKEN Nishina Center, Wako, Saitama 351-0198, Japan
| | - A Estradé
- Department of Physics, Central Michigan University, Mount Pleasant, Michigan 48859, USA
| | - N Fukuda
- RIKEN Nishina Center, Wako, Saitama 351-0198, Japan
| | - M Holl
- Astronomy and Physics Department, Saint Mary's University, Halifax, Nova Scotia B3H 3C3, Canada
- TRIUMF, Vancouver, British Columbia V6T 2A3, Canada
| | - K Itahashi
- RIKEN Nishina Center, Wako, Saitama 351-0198, Japan
| | - N Iwasa
- Department of Physics, Tohoku University, Miyagi 980-8577, Japan
| | - G R Jansen
- Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
- National Center for Computational Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - W G Jiang
- Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - S Kaur
- Astronomy and Physics Department, Saint Mary's University, Halifax, Nova Scotia B3H 3C3, Canada
- Department of Physics and Atmospheric Science, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - A O Macchiavelli
- Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - S Y Matsumoto
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
| | - S Momiyama
- Department of Physics, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - I Murray
- RIKEN Nishina Center, Wako, Saitama 351-0198, Japan
- Institut de Physique Nucleaire, IN2P3, CNRS, Université Paris-Sud, Université Paris-Saclay, 91406 Orsay Cedex, France
| | - T Nakamura
- Department of Physics, Tokyo Institute of Technology, 2-12-1 O-Okayama, Meguro, Tokyo 152-8551, Japan
| | - S J Novario
- Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - H J Ong
- RCNP, Osaka University, Mihogaoka, Ibaraki, Osaka 567 0047, Japan
| | - T Otsuka
- RIKEN Nishina Center, Wako, Saitama 351-0198, Japan
- Department of Physics, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - T Papenbrock
- Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - S Paschalis
- Department of Physics, University of York, Heslington, York YO10 5DD, United Kingdom
| | - A Prochazka
- GSI Helmholtzzentrum für Schwerionenforschung GmbH, D-64291 Darmstadt, Germany
| | - C Scheidenberger
- GSI Helmholtzzentrum für Schwerionenforschung GmbH, D-64291 Darmstadt, Germany
- Justus-Liebig University, 35392 Giessen, Germany
| | - P Schrock
- Center for Nuclear Study, University of Tokyo, RIKEN Campus, Wako, Saitama 351-0198, Japan
| | - Y Shimizu
- RIKEN Nishina Center, Wako, Saitama 351-0198, Japan
| | - D Steppenbeck
- RIKEN Nishina Center, Wako, Saitama 351-0198, Japan
- Center for Nuclear Study, University of Tokyo, RIKEN Campus, Wako, Saitama 351-0198, Japan
| | - H Sakurai
- RIKEN Nishina Center, Wako, Saitama 351-0198, Japan
- Department of Physics, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - D Suzuki
- RIKEN Nishina Center, Wako, Saitama 351-0198, Japan
| | - H Suzuki
- RIKEN Nishina Center, Wako, Saitama 351-0198, Japan
| | - M Takechi
- Graduate School of Science and Technology, Niigata University, Niigata 950-2102, Japan
| | - H Takeda
- RIKEN Nishina Center, Wako, Saitama 351-0198, Japan
| | - S Takeuchi
- Department of Physics, Tokyo Institute of Technology, 2-12-1 O-Okayama, Meguro, Tokyo 152-8551, Japan
| | - R Taniuchi
- Department of Physics, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
- Department of Physics, University of York, Heslington, York YO10 5DD, United Kingdom
| | - K Wimmer
- Department of Physics, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - K Yoshida
- RIKEN Nishina Center, Wako, Saitama 351-0198, Japan
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5
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Ahn DS, Fukuda N, Geissel H, Inabe N, Iwasa N, Kubo T, Kusaka K, Morrissey DJ, Murai D, Nakamura T, Ohtake M, Otsu H, Sato H, Sherrill BM, Shimizu Y, Suzuki H, Takeda H, Tarasov OB, Ueno H, Yanagisawa Y, Yoshida K. Location of the Neutron Dripline at Fluorine and Neon. PHYSICAL REVIEW LETTERS 2019; 123:212501. [PMID: 31809143 DOI: 10.1103/physrevlett.123.212501] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Indexed: 06/10/2023]
Abstract
A search for the heaviest isotopes of fluorine, neon, and sodium was conducted by fragmentation of an intense ^{48}Ca beam at 345 MeV/nucleon with a 20-mm-thick beryllium target and identification of isotopes in the large-acceptance separator BigRIPS at the RIKEN Radioactive Isotope Beam Factory. No events were observed for ^{32,33}F, ^{35,36}Ne, and ^{38}Na and only one event for ^{39}Na after extensive running. Comparison with predicted yields excludes the existence of bound states of these unobserved isotopes with high confidence levels. The present work indicates that ^{31}F and ^{34}Ne are the heaviest bound isotopes of fluorine and neon, respectively. The neutron dripline has thus been experimentally confirmed up to neon for the first time since ^{24}O was confirmed to be the dripline nucleus nearly 20 years ago. These data provide new keys to understanding the nuclear stability at extremely neutron-rich conditions.
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Affiliation(s)
- D S Ahn
- RIKEN Nishina Center for Accelerator-Based Science, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - N Fukuda
- RIKEN Nishina Center for Accelerator-Based Science, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - H Geissel
- GSI, Helmholtzzentrum für Schwerionenforschung GmbH, Planckstraße 1, 64291 Darmstadt, Germany
| | - N Inabe
- RIKEN Nishina Center for Accelerator-Based Science, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - N Iwasa
- Department of Physics, Tohoku University, 6-3, Aramaki Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8578, Japan
| | - T Kubo
- RIKEN Nishina Center for Accelerator-Based Science, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - K Kusaka
- RIKEN Nishina Center for Accelerator-Based Science, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - D J Morrissey
- National Superconducting Cyclotron Laboratory, Michigan State University, 640 South Shaw Lane, East Lansing, Michigan 48824, USA
| | - D Murai
- Department of Physics, Rikkyo University, 3-34-1 Nishi-Ikebukuro, Toshima, Tokyo 171-8501, Japan
| | - T Nakamura
- Department of Physics, Tokyo Institute of Technology, 2-12-1 O-Okayama, Meguro, Tokyo 152-8551, Japan
| | - M Ohtake
- RIKEN Nishina Center for Accelerator-Based Science, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - H Otsu
- RIKEN Nishina Center for Accelerator-Based Science, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - H Sato
- RIKEN Nishina Center for Accelerator-Based Science, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - B M Sherrill
- National Superconducting Cyclotron Laboratory, Michigan State University, 640 South Shaw Lane, East Lansing, Michigan 48824, USA
| | - Y Shimizu
- RIKEN Nishina Center for Accelerator-Based Science, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - H Suzuki
- RIKEN Nishina Center for Accelerator-Based Science, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - H Takeda
- RIKEN Nishina Center for Accelerator-Based Science, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - O B Tarasov
- National Superconducting Cyclotron Laboratory, Michigan State University, 640 South Shaw Lane, East Lansing, Michigan 48824, USA
| | - H Ueno
- RIKEN Nishina Center for Accelerator-Based Science, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Y Yanagisawa
- RIKEN Nishina Center for Accelerator-Based Science, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - K Yoshida
- RIKEN Nishina Center for Accelerator-Based Science, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
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6
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Werner V, Santamaria C, Louchart C, Obertelli A, Doornenbal P, Nowacki F, Authelet G, Baba H, Calvet D, Château F, Corsi A, Delbart A, Gheller JM, Gillibert A, Isobe T, Lapoux V, Matsushita M, Momiyama S, Motobayashi T, Niikura M, Otsu H, Péron C, Peyaud A, Pollacco E, Roussé JY, Sakurai H, Sasano M, Shiga Y, Takeuchi S, Taniuchi R, Uesaka T, Wang H, Yoneda K, Browne F, Chung L, Dombradi Z, Franchoo S, Giacoppo F, Gottardo A, Hadynska-Klek K, Korkulu Z, Koyama S, Kubota Y, Lee J, Lettmann M, Lozeva R, Matsui K, Miyazaki T, Nishimura S, Olivier L, Ota S, Patel Z, Pietralla N, Sahin E, Shand C, Söderström PA, Stefan I, Steppenbeck D, Sumikama T, Suzuki D, Vajta Z, Wu J, Xu Z. Collectivity of neutron-rich Cr and Fe toward N=50. EPJ WEB OF CONFERENCES 2016. [DOI: 10.1051/epjconf/201610703007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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7
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Nakamura T, Kobayashi N, Kondo Y, Satou Y, Tostevin JA, Utsuno Y, Aoi N, Baba H, Fukuda N, Gibelin J, Inabe N, Ishihara M, Kameda D, Kubo T, Motobayashi T, Ohnishi T, Orr NA, Otsu H, Otsuka T, Sakurai H, Sumikama T, Takeda H, Takeshita E, Takechi M, Takeuchi S, Togano Y, Yoneda K. Deformation-driven p-wave halos at the drip line: 31Ne. PHYSICAL REVIEW LETTERS 2014; 112:142501. [PMID: 24765946 DOI: 10.1103/physrevlett.112.142501] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Indexed: 06/03/2023]
Abstract
The halo structure of 31Ne is studied using 1n-removal reactions on C and Pb targets at 230 MeV/nucleon. A combined analysis of the cross sections of these nuclear and Coulomb dominated reactions that feed directly the 30Ne ground-state reveals 31Ne to have a small neutron separation energy, 0.15(-0.10)(+0.16) MeV, and spin-parity 3/2-. Consistency of the data with reaction and large-scale shell-model calculations identifies 31Ne as deformed and having a significant p-wave halo component, suggesting that halos are more frequent occurrences at the neutron drip line.
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Affiliation(s)
- T Nakamura
- Department of Physics, Tokyo Institute of Technology, 2-12-1 O-Okayama, Meguro, Tokyo 152-8551, Japan
| | - N Kobayashi
- Department of Physics, Tokyo Institute of Technology, 2-12-1 O-Okayama, Meguro, Tokyo 152-8551, Japan
| | - Y Kondo
- Department of Physics, Tokyo Institute of Technology, 2-12-1 O-Okayama, Meguro, Tokyo 152-8551, Japan
| | - Y Satou
- Department of Physics, Tokyo Institute of Technology, 2-12-1 O-Okayama, Meguro, Tokyo 152-8551, Japan and Department of Physics and Astronomy, Seoul National University, 599 Gwanak, Seoul 151-742, Republic of Korea
| | - J A Tostevin
- Department of Physics, University of Surrey, Guildford, Surrey, GU2 7XH, United Kingdom
| | - Y Utsuno
- Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195, Japan
| | - N Aoi
- RIKEN Nishina Center, Hirosawa 2-1, Wako, Saitama 351-0198, Japan
| | - H Baba
- RIKEN Nishina Center, Hirosawa 2-1, Wako, Saitama 351-0198, Japan
| | - N Fukuda
- RIKEN Nishina Center, Hirosawa 2-1, Wako, Saitama 351-0198, Japan
| | - J Gibelin
- LPC-ENSICAEN, IN2P3-CNRS et Université de Caen, F-14050, Caen Cedex, France
| | - N Inabe
- RIKEN Nishina Center, Hirosawa 2-1, Wako, Saitama 351-0198, Japan
| | - M Ishihara
- RIKEN Nishina Center, Hirosawa 2-1, Wako, Saitama 351-0198, Japan
| | - D Kameda
- RIKEN Nishina Center, Hirosawa 2-1, Wako, Saitama 351-0198, Japan
| | - T Kubo
- RIKEN Nishina Center, Hirosawa 2-1, Wako, Saitama 351-0198, Japan
| | - T Motobayashi
- RIKEN Nishina Center, Hirosawa 2-1, Wako, Saitama 351-0198, Japan
| | - T Ohnishi
- RIKEN Nishina Center, Hirosawa 2-1, Wako, Saitama 351-0198, Japan
| | - N A Orr
- LPC-ENSICAEN, IN2P3-CNRS et Université de Caen, F-14050, Caen Cedex, France
| | - H Otsu
- RIKEN Nishina Center, Hirosawa 2-1, Wako, Saitama 351-0198, Japan
| | - T Otsuka
- Center for Nuclear Study (CNS), the University of Tokyo, Hongo, Tokyo 113-0033, Japan
| | - H Sakurai
- RIKEN Nishina Center, Hirosawa 2-1, Wako, Saitama 351-0198, Japan
| | - T Sumikama
- Department of Physics, Tokyo University of Science, Chiba 278-8510, Japan
| | - H Takeda
- RIKEN Nishina Center, Hirosawa 2-1, Wako, Saitama 351-0198, Japan
| | - E Takeshita
- RIKEN Nishina Center, Hirosawa 2-1, Wako, Saitama 351-0198, Japan
| | - M Takechi
- RIKEN Nishina Center, Hirosawa 2-1, Wako, Saitama 351-0198, Japan
| | - S Takeuchi
- RIKEN Nishina Center, Hirosawa 2-1, Wako, Saitama 351-0198, Japan
| | - Y Togano
- Department of Physics, Tokyo Institute of Technology, 2-12-1 O-Okayama, Meguro, Tokyo 152-8551, Japan and RIKEN Nishina Center, Hirosawa 2-1, Wako, Saitama 351-0198, Japan
| | - K Yoneda
- RIKEN Nishina Center, Hirosawa 2-1, Wako, Saitama 351-0198, Japan
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8
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Doornenbal P, Scheit H, Takeuchi S, Aoi N, Li K, Matsushita M, Steppenbeck D, Wang H, Baba H, Crawford H, Hoffman CR, Hughes R, Ideguchi E, Kobayashi N, Kondo Y, Lee J, Michimasa S, Motobayashi T, Sakurai H, Takechi M, Togano Y, Winkler R, Yoneda K. In-beam γ-ray spectroscopy of ^34,36,38Mg: merging the N=20 and N=28 shell quenching. PHYSICAL REVIEW LETTERS 2013; 111:212502. [PMID: 24313483 DOI: 10.1103/physrevlett.111.212502] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2013] [Revised: 09/30/2013] [Indexed: 06/02/2023]
Abstract
Neutron-rich N=22, 24, 26 magnesium isotopes were studied via in-beam γ-ray spectroscopy at the RIKEN Radioactive Isotope Beam Factory following secondary fragmentation reactions on a carbon target at ≈200 MeV/nucleon. In the one- and two-proton removal channels from 39Al and 40Si beams, two distinct γ-ray transitions were observed in 38Mg, while in the one-proton removal reaction from 37Al a new transition was observed in addition to the known 2(1)(+)→0(g.s.)(+) decay. From the experimental systematics and comparison to theoretical predictions it is concluded that the transitions belong to the 2(1)(+)→0(g.s.)(+) and 4(1)(+)→2(1)(+) decays in 36Mg and 38Mg, respectively. For 34Mg, previously reported 2(1)(+) and 4(1)(+) level energies were remeasured. The deduced E(4(1)(+))/E(2(1)(+)) ratios for 34,36,38Mg of 3.14(5), 3.07(5), and 3.07(5) are almost identical and suggest the emergence of a large area of deformation extending from the N=20 to the N=28 shell quenching.
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Affiliation(s)
- P Doornenbal
- RIKEN Nishina Center, Wako, Saitama 351-0198, Japan
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9
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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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10
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Wimmer K, Kröll T, Krücken R, Bildstein V, Gernhäuser R, Bastin B, Bree N, Diriken J, Van Duppen P, Huyse M, Patronis N, Vermaelen P, Voulot D, Van de Walle J, Wenander F, Fraile LM, Chapman R, Hadinia B, Orlandi R, Smith JF, Lutter R, Thirolf PG, Labiche M, Blazhev A, Kalkühler M, Reiter P, Seidlitz M, Warr N, Macchiavelli AO, Jeppesen HB, Fiori E, Georgiev G, Schrieder G, Das Gupta S, Lo Bianco G, Nardelli S, Butterworth J, Johansen J, Riisager K. Discovery of the shape coexisting 0+ state in 32 Mg by a two neutron transfer reaction. PHYSICAL REVIEW LETTERS 2010; 105:252501. [PMID: 21231582 DOI: 10.1103/physrevlett.105.252501] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2010] [Indexed: 05/30/2023]
Abstract
The "island of inversion" nucleus 32 Mg has been studied by a (t, p) two neutron transfer reaction in inverse kinematics at REX-ISOLDE. The shape coexistent excited 0+ state in 32 Mg has been identified by the characteristic angular distribution of the protons of the Δ L=0 transfer. The excitation energy of 1058 keV is much lower than predicted by any theoretical model. The low γ-ray intensity observed for the decay of this 0+ state indicates a lifetime of more than 10 ns. Deduced spectroscopic amplitudes are compared with occupation numbers from shell-model calculations.
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Affiliation(s)
- K Wimmer
- Physik Department E12, Technische Universität München, 85748 Garching, Germany
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11
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Nakamura T, Kobayashi N, Kondo Y, Satou Y, Aoi N, Baba H, Deguchi S, Fukuda N, Gibelin J, Inabe N, Ishihara M, Kameda D, Kawada Y, Kubo T, Kusaka K, Mengoni A, Motobayashi T, Ohnishi T, Ohtake M, Orr NA, Otsu H, Otsuka T, Saito A, Sakurai H, Shimoura S, Sumikama T, Takeda H, Takeshita E, Takechi M, Takeuchi S, Tanaka K, Tanaka KN, Tanaka N, Togano Y, Utsuno Y, Yoneda K, Yoshida A, Yoshida K. Halo structure of the island of inversion nucleus 31Ne. PHYSICAL REVIEW LETTERS 2009; 103:262501. [PMID: 20366309 DOI: 10.1103/physrevlett.103.262501] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2009] [Indexed: 05/29/2023]
Abstract
The cross sections for single-neutron removal from the very neutron-rich nucleus 31Ne on Pb and C targets have been measured at 230 MeV/nucleon using the RIBF facility at RIKEN. The deduced large Coulomb breakup cross section of 540(70) mb is indicative of a soft E1 excitation. Comparison with direct-breakup model calculations suggests that the valence neutron of 31Ne occupies a low-l orbital (most probably 2p(3/2)) with a small separation energy (S(n) approximately < 0.8 MeV), instead of being predominantly in the 1f(7/2) orbital as expected from the conventional shell ordering. These findings suggest that 31Ne is the heaviest halo system known.
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Affiliation(s)
- T Nakamura
- Department of Physics, Tokyo Institute of Technology, 2-12-1 O-Okayama, Meguro, Tokyo 152-8551, Japan
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