Excited states and reduced transition probabilities in 
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mmultiscripts><mml:mi mathvariant="bold">Os</mml:mi><mml:mprescripts /><mml:none /><mml:mn>168</mml:mn></mml:mmultiscripts></mml:math>

Grahn, T.; Stolze, S.; Joss, D. T.; Page, R. D.; Sayğı, B.; O’Donnell, D.; Akmali, M.; Andgren, K.; Bianco, L.; Cullen, D. M.; Dewald, Α.; Greenlees, P. T.; Heyde, K.; Iwasaki, H.; Jakobsson, U.; Jones, P.; Judson, D. S.; Julin, R.; Juutinen, S.; Ketelhut, S.; Leino, M.; Lumley, N. M.; Mason, P.; Möller, O.; Nomura, K.; Nyman, M.; Petts, A.; Peura, P.; Pietralla, N.; Pissulla, Th.; Rahkila, P.; Sapple, P. J.; Sarén, J.; Scholey, C.; Simpson, John; Sorri, J.; Stevenson, P. D.; Uusitalo, J.; Watkins, H. V.; Wood, John L.

doi:10.1103/physrevc.94.044327

Cited by 27 publications

(23 citation statements)

References 45 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It is worth pointing out that for 168 Os Grahn et al [23] measured a reduced transition probability for the yrast 4 + resulting in B 4/2 = B(E 2; 4 + 1 → 2 + 1 )/(B(E 2; 2 + 1 → 0 + 1 ) = 0.34 (18). A B 4/2 < 1 is very rare throughout the nuclear chart, with only a handful of examples away from closed shell nuclei, e.g., 48,50 Cr [24], 72,74 Zn [25], 114 Te [26], 114 Xe [27], 166 W [28], 168 Os [23], and 172 Pt [29]. These observations have not been reproduced so far by any type of state-of-the-art nuclear structure calculations, neither large-scale shell models nor beyond-mean-field models.…”

Section: Introductionmentioning

confidence: 99%

“…More recent studies concerning neutron-deficient Os isotopes such as 162 Os [21], including a lifetime measurement of the 17/2 + state in 167 Os [22] and of yrast and non-yrast states in 168 Os [23], give evidence for a shape transition from prolate deformation via γ -soft nuclei to spherical shapes close to the N = 82 shell gap. It is worth pointing out that for 168 Os Grahn et al [23] measured a reduced transition probability for the yrast 4 + resulting in B 4/2 = B(E 2; 4 + 1 → 2 + 1 )/(B(E 2; 2 + 1 → 0 + 1 ) = 0.34 (18). A B 4/2 < 1 is very rare throughout the nuclear chart, with only a handful of examples away from closed shell nuclei, e.g., 48,50 Cr [24], 72,74 Zn [25], 114 Te [26], 114 Xe [27], 166 W [28], 168 Os [23], and 172 Pt [29].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

B(E2) anomalies in the yrast band of Os170

et al. 2019

View full text Add to dashboard Cite

Background:The neutron-deficient osmium isotopic chain provides a great laboratory for the study of shape evolution, with the transition from the soft triaxial rotor in 168 Os to the well-deformed prolate rotor in 180 Os, while shape coexistence appears around N = 96 in 172 Os. Therefore, the study of the Os isotopic chain should provide a better understanding of shape changes in nuclei and a detailed scrutiny of nuclear structure calculations. In this paper, the lifetimes of the low-lying yrast states of 170 Os have been measured for the first time to investigate the shape evolution with neutron number. Purpose: Lifetimes of excited states in the ground-state band of 170 Os are measured to investigate the shape evolution with neutron number in osmium isotopes and compare with state-of-the-art calculations. Methods: The states of interest were populated via the fusion-evaporation reaction 142 Nd( 32 S, 4n) at a bombarding energy of 170 MeV at the ALTO facility from IPN (Orsay, France). Lifetimes of the 2 + 1 and 4 + 1 states in 170 Os were measured with the recoil-distance Doppler-shift method using the Orsay universal plunger system.Results: Lifetimes of the two first excited states in 170 Os were measured for the first time. A very small B(E 2; 4 + 1 → 2 + 1 )/B(E 2; 2 + 1 → 0 + 1 ) = 0.38(11) was found, which is very uncharacteristic for collective nuclei. These results were compared to state-of-the-art beyond-mean-field calculations. Conclusions: Although theoretical results give satisfactory results for the energy of the first few excited states in 170 Os and the B(E 2; 2 + 1 → 0 + 1 ) they fail to reproduce the very small B(E 2; 4 + 1 → 2 + 1 ), which remains a puzzle.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

B(E2) anomalies in the yrast band of Os170

et al. 2019

View full text Add to dashboard Cite

show abstract

“…Therafter will B(E2:2 + 1 → 0 + gs ) and B(E2:4 + 1 → 2 + 1 ) decrease and increase, respectively, until the subshell is filled. Hence, in this scenario, B 4/2 < 1 may occur around midshell and thereafter increase rapidly as a function of n. Interestingly, such textbook patterns of seniority symmetry are quite rare, although a handful of cases with B 4/2 < 1 in magic and near magic nuclei in the lead, tin, and some other regions have been observed [37][38][39][40][42][43][44]. Fig.…”

mentioning

confidence: 99%

“…The experimental data are from this work, Refs. [42,43,48], and from [49]. Some of the data points have been shifted slightly to the left or right for better legibility.…”

mentioning

confidence: 99%

“…This unusual situation indicates that the W, Os, and Pt nuclides with N ≤ 94 might obey seniority symmetry, despite the fact that they are four or more protons and eight or more neutrons removed from the nearest closed shells at Z or N = 82. It should be noted that seniority symmetry was previously mentioned and excluded as a plausible scenario in the cases of 168 Os [42] and 166 W [43] for this particular reason. However, the nuclei for which B 4/2 < 1 in Fig.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Lifetime Measurements of Excited States in Pt172 and the Variation of Quadrupole Transition Strength with Angular Momentum

Cederwall¹,

Doncel²,

Aktaş³

et al. 2018

Phys. Rev. Lett.

Self Cite

View full text Add to dashboard Cite

Lifetimes of the first excited 2^{+} and 4^{+} states in the extremely neutron-deficient nuclide ^{172}Pt have been measured for the first time using the recoil-distance Doppler shift and recoil-decay tagging techniques. An unusually low value of the ratio B(E2:4_{1}^{+}→2_{1}^{+})/B(E2:2_{1}^{+}→0_{gs}^{+})=0.55(19) was found, similar to a handful of other such anomalous cases observed in the entire Segré chart. The observation adds to a cluster of a few extremely neutron-deficient nuclides of the heavy transition metals with neutron numbers N≈90-94 featuring the effect. No theoretical model calculations reported to date have been able to explain the anomalously low B(E2:4_{1}^{+}→2_{1}^{+})/B(E2:2_{1}^{+}→0_{gs}^{+}) ratios observed in these cases. Such low values cannot, e.g., be explained within the framework of the geometrical collective model or by algebraic approaches within the interacting boson model framework. It is proposed that the group of B(E2:4_{1}^{+}→2_{1}^{+})/B(E2:2_{1}^{+}→0_{gs}^{+}) ratios in the extremely neutron-deficient even-even W, Os, and Pt nuclei around neutron numbers N≈90-94 reveal a quantum phase transition from a seniority-conserving structure to a collective regime as a function of neutron number. Although a system governed by seniority symmetry is the only theoretical framework for which such an effect may naturally occur, the phenomenon is highly unexpected for these nuclei that are not situated near closed shells.

show abstract

Charged-Particle Radioactive Decays

Blank¹,

Page²

2022

Handbook of Nuclear Physics

View full text Add to dashboard Cite

Excited states and reduced transition probabilities in Os168

Cited by 27 publications

References 45 publications

B(E2) anomalies in the yrast band of Os170

B(E2) anomalies in the yrast band of Os170

Lifetime Measurements of Excited States in Pt172 and the Variation of Quadrupole Transition Strength with Angular Momentum

Charged-Particle Radioactive Decays

Contact Info

Product

Resources

About