Physics Letters B (Mar 2020)

Isomer studies in the vicinity of the doubly-magic nucleus 100Sn: Observation of a new low-lying isomeric state in 97Ag

  • Christine Hornung,
  • Daler Amanbayev,
  • Irene Dedes,
  • Gabriella Kripko-Koncz,
  • Ivan Miskun,
  • Noritaka Shimizu,
  • Samuel Ayet San Andrés,
  • Julian Bergmann,
  • Timo Dickel,
  • Jerzy Dudek,
  • Jens Ebert,
  • Hans Geissel,
  • Magdalena Górska,
  • Hubert Grawe,
  • Florian Greiner,
  • Emma Haettner,
  • Takaharu Otsuka,
  • Wolfgang R. Plaß,
  • Sivaji Purushothaman,
  • Ann-Kathrin Rink,
  • Christoph Scheidenberger,
  • Helmut Weick,
  • Soumya Bagchi,
  • Andrey Blazhev,
  • Olga Charviakova,
  • Dominique Curien,
  • Andrew Finlay,
  • Satbir Kaur,
  • Wayne Lippert,
  • Jan-Hendrik Otto,
  • Zygmunt Patyk,
  • Stephane Pietri,
  • Yoshiki K. Tanaka,
  • Yusuke Tsunoda,
  • John S. Winfield

Journal volume & issue
Vol. 802

Abstract

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Long-lived isomeric states in 97Ag and 101−109In were investigated with the FRS Ion Catcher at GSI. In the isotope 97Ag, a long-lived (1/2−) isomeric state was discovered, and its excitation energy was determined to be 618(38) keV. This is simultaneously the first discovery of a nuclear isomeric state by multiple-reflection time-of-flight mass spectrometry. The measured excitation energies were compared to large-scale shell-model calculations, which indicated the importance of core excitation around 100Sn. Furthermore, advanced mean-field calculations for the 97Ag nucleus and relevant neighboring nuclei were performed, which have contributed to a better understanding of the repetitive appearance of certain isomeric structures in neighboring nuclei, and which have supported the discovery of the isomeric state in 97Ag in a global shell-evolution scheme. Keywords: Mass spectrometry, Multiple-reflection time-of-flight mass spectrometry, Nuclear structure, Isomers, Isomer-to-ground state ratio, Exotic nuclei