Physics Letters B (2020-01-01)

Shell evolution of N = 40 isotones towards 60Ca: First spectroscopy of 62Ti

  • M.L. Cortés,
  • W. Rodriguez,
  • P. Doornenbal,
  • A. Obertelli,
  • J.D. Holt,
  • S.M. Lenzi,
  • J. Menéndez,
  • F. Nowacki,
  • K. Ogata,
  • A. Poves,
  • T.R. Rodríguez,
  • A. Schwenk,
  • J. Simonis,
  • S.R. Stroberg,
  • K. Yoshida,
  • L. Achouri,
  • H. Baba,
  • F. Browne,
  • D. Calvet,
  • F. Château,
  • S. Chen,
  • N. Chiga,
  • A. Corsi,
  • A. Delbart,
  • J.-M. Gheller,
  • A. Giganon,
  • A. Gillibert,
  • C. Hilaire,
  • T. Isobe,
  • T. Kobayashi,
  • Y. Kubota,
  • V. Lapoux,
  • H.N. Liu,
  • T. Motobayashi,
  • I. Murray,
  • H. Otsu,
  • V. Panin,
  • N. Paul,
  • H. Sakurai,
  • M. Sasano,
  • D. Steppenbeck,
  • L. Stuhl,
  • Y.L. Sun,
  • Y. Togano,
  • T. Uesaka,
  • K. Wimmer,
  • K. Yoneda,
  • O. Aktas,
  • T. Aumann,
  • L.X. Chung,
  • F. Flavigny,
  • S. Franchoo,
  • I. Gašparić,
  • R.-B. Gerst,
  • J. Gibelin,
  • K.I. Hahn,
  • D. Kim,
  • T. Koiwai,
  • Y. Kondo,
  • P. Koseoglou,
  • J. Lee,
  • C. Lehr,
  • B.D. Linh,
  • T. Lokotko,
  • M. MacCormick,
  • K. Moschner,
  • T. Nakamura,
  • S.Y. Park,
  • D. Rossi,
  • E. Sahin,
  • D. Sohler,
  • P.-A. Söderström,
  • S. Takeuchi,
  • H. Toernqvist,
  • V. Vaquero,
  • V. Wagner,
  • S. Wang,
  • V. Werner,
  • X. Xu,
  • H. Yamada,
  • D. Yan,
  • Z. Yang,
  • M. Yasuda,
  • L. Zanetti

Journal volume & issue
Vol. 800

Abstract

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Excited states in the N=40 isotone 62Ti were populated via the 63V(p,2p)62Ti reaction at ∼200 MeV/nucleon at the Radioactive Isotope Beam Factory and studied using γ-ray spectroscopy. The energies of the 21+→0gs+ and 41+→21+ transitions, observed here for the first time, indicate a deformed 62Ti ground state. These energies are increased compared to the neighboring 64Cr and 66Fe isotones, suggesting a small decrease of quadrupole collectivity. The present measurement is well reproduced by large-scale shell-model calculations based on effective interactions, while ab initio and beyond mean-field calculations do not yet reproduce our findings. The shell-model calculations for 62Ti show a dominant configuration with four neutrons excited across the N=40 gap. Likewise, they indicate that the N=40 island of inversion extends down to Z=20, disfavoring a possible doubly magic character of the elusive 60Ca. Keywords: Shell evolution, Radioactive beams, Gamma-ray spectroscopy