First observation of a shape isomer and a low-lying strongly-coupled prolate band in neutron-deficient semi-magic 187Pb

Zhang, W.Q.; Andreyev, A. N.; Liu, Zhong; Seweryniak, D.; Huang, Hsiang-Cheh; Li, Z.H.; Li, J.G.; Guo, C.Y.; Doherty, D. T.; Barzakh, A. E.; Duppen, P. Van; Cubiss, J. G.; Andel, B.; Antalic, S.; Block, M.; Bronis, A.; Carpenter, M. P.; Copp, P.; Ding, B.; Favier, Z.; Giacoppo, F.; Huang, T. H.; Yu, X.H.; Kindler, B.; Kondev, F. G.; Lauritsen, T.; Li, G.S.; Lommel, B.; Lu, Haiyan; Monthery, M. Al; Mošať, P.; Niu, Y. F.; Raison, C.; Reviol, W.; Savard, G.; Stolze, S.; Wilson, G. L.; Wu, H. y.; Wang, Zhi Heng; Xu, F. R.; Zeng, Q.; Zhou, X. H.

doi:10.1016/j.physletb.2022.137129

Cited by 5 publications

(3 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The parabolic behaviour of the intruder states is now more evident at the minima that take place at N = 104 and N = 106 for prolate and oblate configurations, respectively. This is also well in-line with the very recent study on the odd-mass 187 Pb nucleus with N = 105 which shows that the prolate minimum is below the oblate one in energy 41 .…”

Section: An Intensity Value Ofsupporting

confidence: 91%

Reassigning the shapes of the 0+ states in the 186Pb nucleus

et al. 2022

View full text Add to dashboard Cite

Across the physics disciplines, the 186Pb nucleus is the only known system, where the two first excited states, together with the ground state, form a triplet of zero-spin states assigned with prolate, oblate and spherical shapes. Here we report on a precision measurement where the properties of collective transitions in 186Pb were determined in a simultaneous in-beam γ-ray and electron spectroscopy experiment employing the recoil-decay tagging technique. The feeding of the $${0}_{2}^{+}$$ 0 2 + state and the interband $${2}_{2}^{+}\to {2}_{1}^{+}$$ 2 2 + → 2 1 + transition have been observed. We also present direct measurement of the energies of the electric monopole transitions from the excited 0+ states to the 0+ ground state. In contrast to the earlier understanding, the obtained reduced transition probability $$B(E2;{2}_{1}^{+}\to {0}_{2}^{+})$$ B ( E 2 ; 2 1 + → 0 2 + ) value of 190(80) W.u., the transitional quadrupole moment $$| {Q}_{t}({2}_{1}^{+}\to {0}_{2}^{+})| =7.7$$ ∣ Q t ( 2 1 + → 0 2 + ) ∣ = 7.7 (33) eb and intensity balance arguments provide evidence to reassign the $${0}_{2}^{+}$$ 0 2 + and $${0}_{3}^{+}$$ 0 3 + states with predominantly prolate and oblate shape, respectively. Our work demonstrates a step-up in experimental sensitivity and paves the way for systematic studies of electric monopole transitions in this region. These electric monopole transitions probe the nuclear volume in a unique manner and provide unexploited input for development of the next-generation energy density functional models.

show abstract

Section: An Intensity Value Ofsupporting

confidence: 91%

Reassigning the shapes of the 0+ states in the 186Pb nucleus

et al. 2022

View full text Add to dashboard Cite

show abstract

“…The RDT efficiency can be deduced as the ratio of the number of prompt γ rays from the RDT [γ (GS)-EVR]-α The RDT spectra for 187 Pb g,m were shown in Ref. [35]. To deduce the RDT efficiencies we considered the relevant transitions feeding to respective 3/2 − and 13/2 + states, and we avoided double counting of the γ rays within the respective bands.…”

Section: The Rdt Efficiencies For Different Nucleimentioning

confidence: 99%

“…The data for 187 Pb and for 183 Hg from the same experiment were previously presented in Refs. [35,36].…”

Section: Introductionmentioning

confidence: 99%

Identification of excited states in Bi188 and Po188

Zhang¹,

Andreyev²,

Liu³

et al. 2022

Phys. Rev. C

Self Cite

View full text Add to dashboard Cite

The neutron-deficient 188 Bi and 188 Po isotopes have been studied by γ -ray spectroscopy using the recoil-decay tagging technique with the Argonne Gas-Filled Analyzer. A new 0.25(5)-μs isomeric state and a prompt cascade formed by 319-, 366-, and 462-keV γ rays have been established on top of the (10 − ) α-decaying isomer in 188 Bi. The first excited (2 + ) state in 188 Po was identified, its excitation energy of 242(2) keV continues the nearly constant trend for the first 2 + states in 190,192,194 Po. The state is most likely a member of a prolate rotational band built on the ground state, albeit mixing with other coexisting configurations cannot be excluded. The new results obtained in the present work provide new information to shape coexistence in bismuth and polonium isotopes near the neutron midshell at N = 104. In this mass region, a reduction in the prompt γ -ray yield obtained with recoil decay tagging was observed for a few nuclides, and the possible reasons are presented.

show abstract