Quadrupole and octupole collectivity in the semi-magic nucleus ²⁰⁶₈₀Hg₁₂₆

Summary, in English

The first low-energy Coulomb-excitation measurement of the radioactive, semi-magic, two proton-hole nucleus ²⁰⁶Hg, was performed at CERN's recently-commissioned HIE-ISOLDE facility. Two γ rays depopulating low-lying states in ²⁰⁶Hg were observed. From the data, a reduced transition strength B(E2; 2⁺₁ → 0⁺₁) = 4.4(6) W.u. was determined, the first such value for an N=126 nucleus south of ²⁰⁸Pb,
which is found to be slightly lower than that predicted by shell-model
calculations. In addition, a collective octupole state was identified at
an excitation energy of 2705 keV, for which a reduced B(E3) transition probability of 30⁺¹⁰_-30 W.u. was extracted. These results are crucial for understanding both
quadrupole and octupole collectivity in the vicinity of the heaviest
doubly-magic nucleus ²⁰⁸Pb, and for benchmarking a number of
theoretical approaches in this key region. This is of particular
importance given the paucity of data on transition strengths in this
region, which could be used, in principle, to test calculations relevant
to the astrophysical r-process.

• Author: L. Morrison; K. Hadyńska-Klȩk; Zs. Podolyák; L.P. Gaffney; M. Zielińska; B.A. Brown; H. Grawe; P.D. Stevenson; T. Berry; A. Boukhari; M. Brunet; R. Canavan; R. Catherall; J. Cederkäll; S.J. Colosimo; J.G. Cubiss; H. De Witte; D.T. Doherty; Ch. Fransen; G. Georgiev; E. Giannopoulos; M. Górska; H. Hess; L. Kaya; T. Kröll; N. Lalović; B. Marsh; Y. Martinez Palenzuela; G. O'Neill; J. Pakarinen; J.P. Ramos; P. Reiter; J.A. Rodriguez; D. Rosiak; S. Rothe; M. Rudigier; M. Siciliano; E. C. Simpson; J. Snall; P. Spagnoletti; S. Thiel; N. Warr; F. Wenander; R. Zidarova
• Department/s: Nuclear physics
• Publishing year: 2023
• Language: English
• Publication/Series: Physics Letters B
• Volume: 838
• Links: http://dx.doi.org/10.1016/j.physletb.2023.137675
• Document type: Journal article
• Publisher: Elsevier
• Topic: Subatomic Physics
• Status: Published
• ISBN/ISSN/Other: ISSN: 0370-2693