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Tang TL, Kay BP, Hoffman CR, Schiffer JP, Sharp DK, Gaffney LP, Freeman SJ, Mumpower MR, Arokiaraj A, Baader EF, Butler PA, Catford WN, de Angelis G, Flavigny F, Gott MD, Gregor ET, Konki J, Labiche M, Lazarus IH, MacGregor PT, Martel I, Page RD, Podolyák Z, Poleshchuk O, Raabe R, Recchia F, Smith JF, Szwec SV, Yang J. First Exploration of Neutron Shell Structure below Lead and beyond N=126. Phys Rev Lett 2020; 124:062502. [PMID: 32109128 DOI: 10.1103/physrevlett.124.062502] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Revised: 12/12/2019] [Accepted: 01/02/2020] [Indexed: 06/10/2023]
Abstract
The nuclei below lead but with more than 126 neutrons are crucial to an understanding of the astrophysical r process in producing nuclei heavier than A∼190. Despite their importance, the structure and properties of these nuclei remain experimentally untested as they are difficult to produce in nuclear reactions with stable beams. In a first exploration of the shell structure of this region, neutron excitations in ^{207}Hg have been probed using the neutron-adding (d,p) reaction in inverse kinematics. The radioactive beam of ^{206}Hg was delivered to the new ISOLDE Solenoidal Spectrometer at an energy above the Coulomb barrier. The spectroscopy of ^{207}Hg marks a first step in improving our understanding of the relevant structural properties of nuclei involved in a key part of the path of the r process.
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Affiliation(s)
- T L Tang
- Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - B P Kay
- Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - C R Hoffman
- Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - J P Schiffer
- Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - D K Sharp
- Department of Physics, University of Manchester, M13 9PL Manchester, United Kingdom
| | | | - S J Freeman
- Department of Physics, University of Manchester, M13 9PL Manchester, United Kingdom
| | - M R Mumpower
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
- Center for Theoretical Astrophysics, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - A Arokiaraj
- KU Leuven, Intituut voor Kern-en Stralingsfysica, Celestijnenlaan 200D, 3001 Leuven, Belgium
| | | | - P A Butler
- Oliver Lodge Laboratory, University of Liverpool, L69 7ZE Liverpool, United Kingdom
| | - W N Catford
- Department of Physics, University of Surrey, Guildford GU2 7XH, United Kingdom
| | - G de Angelis
- Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro, I-35020 Legnaro, Italy
| | - F Flavigny
- Institut de Physique Nucléaire, CNRS-IN2P3, Université Paris-Sud, Université Paris-Saclay, 91406 Orsay, France
- LPC Caen, Normandie Université, ENSICAEN, UNICAEN, CNRS/IN2P3, 14000 Caen, France
| | - M D Gott
- Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - E T Gregor
- Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro, I-35020 Legnaro, Italy
| | - J Konki
- CERN, CH-1211 Geneva, Switzerland
| | - M Labiche
- Nuclear Physics Group, UKRI-STFC Daresbury Laboratory, Daresbury, Warrington WA4 4AD, United Kingdom
| | - I H Lazarus
- Nuclear Physics Group, UKRI-STFC Daresbury Laboratory, Daresbury, Warrington WA4 4AD, United Kingdom
| | - P T MacGregor
- Department of Physics, University of Manchester, M13 9PL Manchester, United Kingdom
| | - I Martel
- Oliver Lodge Laboratory, University of Liverpool, L69 7ZE Liverpool, United Kingdom
| | - R D Page
- Oliver Lodge Laboratory, University of Liverpool, L69 7ZE Liverpool, United Kingdom
| | - Zs Podolyák
- Department of Physics, University of Surrey, Guildford GU2 7XH, United Kingdom
| | - O Poleshchuk
- KU Leuven, Intituut voor Kern-en Stralingsfysica, Celestijnenlaan 200D, 3001 Leuven, Belgium
| | - R Raabe
- KU Leuven, Intituut voor Kern-en Stralingsfysica, Celestijnenlaan 200D, 3001 Leuven, Belgium
| | - F Recchia
- Dipartimento di Fisica e Astronomia, Universit degli Studi di Padova, I-35131 Padova, Italy
- INFN, Sezione di Padova, I-35131 Padova, Italy
| | - J F Smith
- SUPA, School of Computing, Engineering, and Physical Sciences, University of the West of Scotland, Paisley PA1 2BE, United Kingdom
| | - S V Szwec
- Department of Physics, University of Jyvaskyla, P.O. Box 35, FI-40014 Jyvaskyla, Finland
- Helsinki Institute of Physics, University of Helsinki, FIN-00014 Helsinki, Finland
| | - J Yang
- KU Leuven, Intituut voor Kern-en Stralingsfysica, Celestijnenlaan 200D, 3001 Leuven, Belgium
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Scheck M, Mishev S, Ponomarev VY, Chapman R, Gaffney LP, Gregor ET, Pietralla N, Spagnoletti P, Savran D, Simpson GS. Investigating the Pygmy Dipole Resonance Using β Decay. Phys Rev Lett 2016; 116:132501. [PMID: 27081972 DOI: 10.1103/physrevlett.116.132501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Indexed: 06/05/2023]
Abstract
In this contribution it is explored whether γ-ray spectroscopy following β decay with high Q values from mother nuclei with low ground-state spin can be exploited as a probe for the pygmy dipole resonance. The suitability of this approach is demonstrated by a comparison between data from photon scattering, ^{136}Xe(γ,γ^{'}), and ^{136}I [J_{0}^{π}=(1^{-})]→^{136}Xe^{*} β-decay data. It is demonstrated that β decay populates 1^{-} levels associated with the pygmy dipole resonance, but only a fraction of those. The complementary insight into the wave functions probed by β decay is elucidated by calculations within the quasiparticle phonon model. It is demonstrated that β decay dominantly populates complex configurations, which are only weakly excited in inelastic scattering experiments.
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Affiliation(s)
- M Scheck
- School of Engineering and Computing, University of the West of Scotland, Paisley PA1 2BE, United Kingdom
- SUPA, Scottish Universities Physics Alliance, Glasgow G12 8QQ, United Kingdom
| | - S Mishev
- JINR, Joint Institute for Nuclear Research, Dubna 141980, Russia
- Institute for Advanced Physical Studies, New Bulgarian University, Sofia 1618, Bulgaria
| | - V Yu Ponomarev
- Institut für Kernphysik, Technische Universität Darmstadt, D-64289 Darmstadt, Germany
| | - R Chapman
- School of Engineering and Computing, University of the West of Scotland, Paisley PA1 2BE, United Kingdom
- SUPA, Scottish Universities Physics Alliance, Glasgow G12 8QQ, United Kingdom
| | - L P Gaffney
- School of Engineering and Computing, University of the West of Scotland, Paisley PA1 2BE, United Kingdom
- SUPA, Scottish Universities Physics Alliance, Glasgow G12 8QQ, United Kingdom
| | - E T Gregor
- School of Engineering and Computing, University of the West of Scotland, Paisley PA1 2BE, United Kingdom
- SUPA, Scottish Universities Physics Alliance, Glasgow G12 8QQ, United Kingdom
| | - N Pietralla
- Institut für Kernphysik, Technische Universität Darmstadt, D-64289 Darmstadt, Germany
| | - P Spagnoletti
- School of Engineering and Computing, University of the West of Scotland, Paisley PA1 2BE, United Kingdom
- SUPA, Scottish Universities Physics Alliance, Glasgow G12 8QQ, United Kingdom
| | - D Savran
- ExtreMe Matter Institute EMMI and Research Division, GSI Helmholtzzentrum für Schwerionenforschung, D-64291 Darmstadt, Germany
| | - G S Simpson
- School of Engineering and Computing, University of the West of Scotland, Paisley PA1 2BE, United Kingdom
- SUPA, Scottish Universities Physics Alliance, Glasgow G12 8QQ, United Kingdom
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Bucher B, Zhu S, Wu CY, Janssens RVF, Cline D, Hayes AB, Albers M, Ayangeakaa AD, Butler PA, Campbell CM, Carpenter MP, Chiara CJ, Clark JA, Crawford HL, Cromaz M, David HM, Dickerson C, Gregor ET, Harker J, Hoffman CR, Kay BP, Kondev FG, Korichi A, Lauritsen T, Macchiavelli AO, Pardo RC, Richard A, Riley MA, Savard G, Scheck M, Seweryniak D, Smith MK, Vondrasek R, Wiens A. Direct Evidence of Octupole Deformation in Neutron-Rich ^{144}Ba. Phys Rev Lett 2016; 116:112503. [PMID: 27035298 DOI: 10.1103/physrevlett.116.112503] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Indexed: 06/05/2023]
Abstract
The neutron-rich nucleus ^{144}Ba (t_{1/2}=11.5 s) is expected to exhibit some of the strongest octupole correlations among nuclei with mass numbers A less than 200. Until now, indirect evidence for such strong correlations has been inferred from observations such as enhanced E1 transitions and interleaving positive- and negative-parity levels in the ground-state band. In this experiment, the octupole strength was measured directly by sub-barrier, multistep Coulomb excitation of a post-accelerated 650-MeV ^{144}Ba beam on a 1.0-mg/cm^{2} ^{208}Pb target. The measured value of the matrix element, ⟨3_{1}^{-}∥M(E3)∥0_{1}^{+}⟩=0.65(+17/-23) eb^{3/2}, corresponds to a reduced B(E3) transition probability of 48(+25/-34) W.u. This result represents an unambiguous determination of the octupole collectivity, is larger than any available theoretical prediction, and is consistent with octupole deformation.
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Affiliation(s)
- B Bucher
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - S Zhu
- Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - C Y Wu
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - R V F Janssens
- Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - D Cline
- University of Rochester, Rochester, New York 14627, USA
| | - A B Hayes
- University of Rochester, Rochester, New York 14627, USA
| | - M Albers
- Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - A D Ayangeakaa
- Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - P A Butler
- University of Liverpool, Liverpool L69 7ZE, United Kingdom
| | - C M Campbell
- Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - M P Carpenter
- Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - C J Chiara
- Argonne National Laboratory, Argonne, Illinois 60439, USA
- University of Maryland, College Park, Maryland 20742, USA
| | - J A Clark
- Argonne National Laboratory, Argonne, Illinois 60439, USA
| | | | - M Cromaz
- Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - H M David
- Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - C Dickerson
- Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - E T Gregor
- University of the West of Scotland, Paisley PA1 2BE, United Kingdom
- SUPA, Scottish Universities Physics Alliance, Glasgow G12 8QQ, United Kingdom
| | - J Harker
- Argonne National Laboratory, Argonne, Illinois 60439, USA
- University of Maryland, College Park, Maryland 20742, USA
| | - C R Hoffman
- Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - B P Kay
- Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - F G Kondev
- Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - A Korichi
- Argonne National Laboratory, Argonne, Illinois 60439, USA
- CSNSM, IN2P3-CNRS, bâtiment 104-108, F-91405 Orsay Campus, France
| | - T Lauritsen
- Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - A O Macchiavelli
- Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - R C Pardo
- Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - A Richard
- Ohio University, Athens, Ohio 45701, USA
| | - M A Riley
- Florida State University, Tallahassee, Florida 32306, USA
| | - G Savard
- Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - M Scheck
- University of the West of Scotland, Paisley PA1 2BE, United Kingdom
- SUPA, Scottish Universities Physics Alliance, Glasgow G12 8QQ, United Kingdom
| | - D Seweryniak
- Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - M K Smith
- University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - R Vondrasek
- Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - A Wiens
- Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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