Long-sought isomer turns out to be the ground state of 76Cu

L. Canete; S. Giraud; A. Kankainen; B. Bastin; F. Nowacki; P. Ascher; T. Eronen; V. Girard Alcindor; A. Jokinen; A. Khanam; I.D. Moore; D. Nesterenko; F. De Oliveira; H. Penttilä; C. Petrone; I. Pohjalainen; A. De Roubin; V. Rubchenya; M. Vilen; J. Äystö

Physics Letters B (Jun 2024)

Long-sought isomer turns out to be the ground state of 76Cu

L. Canete,
S. Giraud,
A. Kankainen,
B. Bastin,
F. Nowacki,
P. Ascher,
T. Eronen,
V. Girard Alcindor,
A. Jokinen,
A. Khanam,
I.D. Moore,
D. Nesterenko,
F. De Oliveira,
H. Penttilä,
C. Petrone,
I. Pohjalainen,
A. De Roubin,
V. Rubchenya,
M. Vilen,
J. Äystö

Affiliations

L. Canete: University of Jyväskylä, Department of Physics, Accelerator Laboratory, P.O. Box 35(YFL) FI-40014 University of Jyväskylä, Finland; Department of Physics, University of Surrey, Guildford, GU2 7X5, United Kingdom; Corresponding author at: Northeastern University London, Devon House, 58 St Katharine's Way, E1W 1LP, London, United Kingdom.
S. Giraud: GANIL, Bd Henri Becquerel, BP 55027, F-14076 Caen Cedex 5, France; Department of Physics and Astronomy, and the Facility for Rare Isotope Beams, Michigan State University, East Lansing, MI 48824-1321, USA
A. Kankainen: University of Jyväskylä, Department of Physics, Accelerator Laboratory, P.O. Box 35(YFL) FI-40014 University of Jyväskylä, Finland; Corresponding author at: University of Jyväskylä, P.O. Box 35, FI-40014 University of Jyväskylä, Finland.
B. Bastin: GANIL, Bd Henri Becquerel, BP 55027, F-14076 Caen Cedex 5, France
F. Nowacki: Université de Strasbourg, CNRS, IPHC UMR 7178, F-67000 Strasbourg, France
P. Ascher: LP2i, CNRS/IN2P3Université, Bordeaux 1, 33175 Gradignan Cedex, France
T. Eronen: University of Jyväskylä, Department of Physics, Accelerator Laboratory, P.O. Box 35(YFL) FI-40014 University of Jyväskylä, Finland
V. Girard Alcindor: GANIL, Bd Henri Becquerel, BP 55027, F-14076 Caen Cedex 5, France; Université Paris-Saclay, CNRS/IN2P3, IJCLab, 91405 Orsay, France
A. Jokinen: University of Jyväskylä, Department of Physics, Accelerator Laboratory, P.O. Box 35(YFL) FI-40014 University of Jyväskylä, Finland
A. Khanam: University of Jyväskylä, Department of Physics, Accelerator Laboratory, P.O. Box 35(YFL) FI-40014 University of Jyväskylä, Finland; Department of Applied Physics, Aalto University, P.O. Box 11000, FI-00076 Aalto, Finland; Department of Physics, University of Helsinki, P.O. Box 43, FI-00014 Helsinki, Finland
I.D. Moore: University of Jyväskylä, Department of Physics, Accelerator Laboratory, P.O. Box 35(YFL) FI-40014 University of Jyväskylä, Finland
D. Nesterenko: University of Jyväskylä, Department of Physics, Accelerator Laboratory, P.O. Box 35(YFL) FI-40014 University of Jyväskylä, Finland
F. De Oliveira: GANIL, Bd Henri Becquerel, BP 55027, F-14076 Caen Cedex 5, France
H. Penttilä: University of Jyväskylä, Department of Physics, Accelerator Laboratory, P.O. Box 35(YFL) FI-40014 University of Jyväskylä, Finland
C. Petrone: IFIN-HH, P.O. Box MG-6, 077125 Bucharest-Magurele, Romania
I. Pohjalainen: University of Jyväskylä, Department of Physics, Accelerator Laboratory, P.O. Box 35(YFL) FI-40014 University of Jyväskylä, Finland
A. De Roubin: University of Jyväskylä, Department of Physics, Accelerator Laboratory, P.O. Box 35(YFL) FI-40014 University of Jyväskylä, Finland
V. Rubchenya: University of Jyväskylä, Department of Physics, Accelerator Laboratory, P.O. Box 35(YFL) FI-40014 University of Jyväskylä, Finland
M. Vilen: University of Jyväskylä, Department of Physics, Accelerator Laboratory, P.O. Box 35(YFL) FI-40014 University of Jyväskylä, Finland; Experimental Physics Department, CERN, CH-1211 Geneva 23, Switzerland
J. Äystö: University of Jyväskylä, Department of Physics, Accelerator Laboratory, P.O. Box 35(YFL) FI-40014 University of Jyväskylä, Finland

Journal volume & issue: Vol. 853
p. 138663

Abstract

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Isomers close to the doubly magic nucleus 78Ni (Z=28, N=50) provide essential information on the shell evolution and shape coexistence far from stability. The existence of a long-lived isomeric state in 76Cu has been debated for a long time. We have performed high-precision mass measurements of 76Cu with the JYFLTRAP double Penning trap mass spectrometer at the Ion Guide Isotope Separator On-Line facility and confirm the existence of such an isomeric state with an excitation energy Ex=64.8(25) keV. Based on the ratio of detected ground- and isomeric-state ions as a function of time, we show that the isomer is the shorter-living state previously considered as the ground state of 76Cu. The result can potentially change the conclusions made in previous works related to the spin-parity and charge radius of the 76Cu ground state. Additionally, the new 76Cu(n,γ) reaction Q-value has an impact on the astrophysical rapid neutron-capture process.

Published in Physics Letters B

ISSN: 0370-2693 (Print); 1873-2445 (Online)
Publisher: Elsevier
Country of publisher: Netherlands
LCC subjects: Science: Physics
Website: http://www.journals.elsevier.com/physics-letters-b/

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