Physics Letters B (Sep 2023)

Emergence of triaxiality in 74Se from electric monopole transition strengths

  • N. Marchini,
  • A. Nannini,
  • M. Rocchini,
  • T.R. Rodríguez,
  • M. Ottanelli,
  • N. Gelli,
  • A. Perego,
  • G. Benzoni,
  • N. Blasi,
  • G. Bocchi,
  • D. Brugnara,
  • A. Buccola,
  • G. Carozzi,
  • A. Goasduff,
  • E.T. Gregor,
  • P.R. John,
  • M. Komorowska,
  • D. Mengoni,
  • F. Recchia,
  • S. Riccetto,
  • D. Rosso,
  • A. Saltarelli,
  • M. Siciliano,
  • J.J. Valiente-Dobón,
  • I. Zanon

Journal volume & issue
Vol. 844
p. 138067

Abstract

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The structure of 74Se at low energy was investigated via spectroscopy of internal conversion electrons at the INFN Legnaro National Laboratories (LNL). A set of internal K-conversion coefficients and monopole transition strengths was measured. A large ρ2(E0;22+→21+)⋅103=210(130) value was deduced. This result, in addition to a low upper limit for the 03+→02+ electron transition, casts in doubt a simple interpretation of the 74Se low-lying structure, in particular the recently proposed spherical, vibrational character. New microscopic beyond-mean-field calculations generally agree with the experimental results and are capable of producing a large ρ2(E0;22+→21+) value, even if still a factor ≈7 smaller than the experiment. Triaxiality and a complex shape-coexistence and mixing scenario seem responsible for this unexpected experimental result.

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