Physics Letters B (Dec 2021)

Impact of shell evolution on Gamow-Teller β decay from a high-spin long-lived isomer in 127Ag

  • H. Watanabe,
  • C.X. Yuan,
  • G. Lorusso,
  • S. Nishimura,
  • Z.Y. Xu,
  • T. Sumikama,
  • P.-A. Söderström,
  • P. Doornenbal,
  • F. Browne,
  • G. Gey,
  • H.S. Jung,
  • J. Taprogge,
  • Zs. Vajta,
  • H.K. Wang,
  • J. Wu,
  • A. Yagi,
  • H. Baba,
  • G. Benzoni,
  • K.Y. Chae,
  • F.C.L. Crespi,
  • N. Fukuda,
  • R. Gernhäuser,
  • N. Inabe,
  • T. Isobe,
  • A. Jungclaus,
  • D. Kameda,
  • G.D. Kim,
  • Y.K. Kim,
  • I. Kojouharov,
  • F.G. Kondev,
  • T. Kubo,
  • N. Kurz,
  • Y.K. Kwon,
  • G.J. Lane,
  • Z. Li,
  • C.-B. Moon,
  • A. Montaner-Pizá,
  • K. Moschner,
  • F. Naqvi,
  • M. Niikura,
  • H. Nishibata,
  • D. Nishimura,
  • A. Odahara,
  • R. Orlandi,
  • Z. Patel,
  • Zs. Podolyák,
  • H. Sakurai,
  • H. Schaffner,
  • G.S. Simpson,
  • K. Steiger,
  • H. Suzuki,
  • H. Takeda,
  • A. Wendt,
  • K. Yoshinaga

Journal volume & issue
Vol. 823
p. 136766

Abstract

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The change of the shell structure in atomic nuclei, so-called “nuclear shell evolution”, occurs due to changes of major configurations through particle-hole excitations inside one nucleus, as well as due to variation of the number of constituent protons or neutrons. We have investigated how the shell evolution affects Gamow-Teller (GT) transitions that dominate the β decay in the region below 132Sn using the newly obtained experimental data on a long-lived isomer in 127Ag. The T1/2=67.5(9) ms isomer has been identified with a spin and parity of (27/2+) at an excitation energy of 1942−20+14 keV, and found to decay via an internal transition of an E3 character, which competes with the dominant β-decay branches towards the high-spin states in 127Cd. The underlying mechanism of a strong GT transition from the 127Ag isomer is discussed in terms of configuration-dependent optimization of the effective single-particle energies in the framework of a shell-model approach.

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