| 1. |
- Guo, S., et al.
(author)
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Evidence for pseudospin-chiral quartet bands in the presence of octupole correlations
- 2020
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In: Physics Letters B. - : ELSEVIER. - 0370-2693 .- 1873-2445. ; 807
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Journal article (peer-reviewed)abstract
- Three nearly degenerate pairs of doublet bands are identified in Ba-131. Two of them, with positive-parity, are interpreted as pseudospin-chiral quartet bands. This is the first time that a complete set of chiral doublet bands built on the pseudospin partners pi(d(5/2), g(7/2)) is observed. The chiral bands with opposite parity built on 3-quasiparticle configurations are directly connected by many E1 transitions, without involving an intermediary non-chiral configuration. The observed band structures in Ba-131 have been investigated by using the reflection-asymmetric particle rotor model. The energies and the electromagnetic transition ratios of the three pairs of doublet bands observed in Ba-131 are reproduced and they are interpreted as chiral doublet bands with three-quasiparticle configurations. It is the first time that multiple chiral bands are observed in the presence of enhanced octupole correlations and pseudospin symmetry.
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| 2. |
- Lv, B. F., et al.
(author)
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Evolution from γ -soft to stable triaxiality in Nd 136 as a prerequisite of chirality
- 2018
-
In: Physical Review C. - : American Physical Society. - 2469-9985 .- 2469-9993. ; 98:4
-
Journal article (peer-reviewed)abstract
- The level structure of Nd136 has been investigated using the Mo100(Ar40,4n) reaction and the JUROGAM II+RITU+GREAT setup. The level scheme has been extended significantly. Many new bands have been identified both at low and high spin, among which are five nearly degenerate bands interpreted as chiral partners. Excitation energies, spins, and parities of the previously known bands are revised and firmly established, and some previously known bands have been revised. Configurations are assigned to the observed bands based on cranked Nilsson-Strutinsky calculations. The band structure of Nd136 is now clarified and the various types of single-particle and collective excitations are well understood.
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| 3. |
- Lv, B. F., et al.
(author)
-
Tilted precession bands in Nd 135
- 2021
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In: Physical Review C. - : American Physical Society. - 2469-9985 .- 2469-9993. ; 103:4
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Journal article (peer-reviewed)abstract
- Two new excited bands built on the πh11/2 configuration have been identified in Nd135 in addition to the known πh11/2 band. The energy spectra of the excited bands and the available electromagnetic transition probabilities are in good agreement with theoretical results obtained using quasiparticle-plus-triaxial-rotor model calculations. The properties of the bands identify them as tilted precession bands instead of wobbling bands. Our results give a new insight into the interpretation of the low-lying bands in odd-A mass nuclei, and can stimulate future studies to address the nuclear triaxiality.
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| 4. |
- Lv, B. F., et al.
(author)
-
Evidence against the wobbling nature of low-spin bands in 135Pr
- 2022
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In: Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 824
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Journal article (peer-reviewed)abstract
- The electromagnetic character of the ΔI=1 transitions connecting the 1- to 0-phonon and the 2- to 1-phonon wobbling bands should be dominated by an E2 component, due to the collective motion of the entire nuclear charge. In the present work it is shown, based on combined angular correlation and linear polarization measurements, that the mixing ratios of all analyzed connecting transitions between low-lying bands in 135Pr interpreted as 0-, 1-, and 2-phonon wobbling bands, have absolute values smaller than one. This indicates predominant M1 magnetic character, which is incompatible with the proposed wobbling nature. All experimental observables are instead in good agreement with quasiparticle-plus-triaxial-rotor model calculations, which describe the bands as resulting from a rapid re-alignment of the total angular momentum from the short to the intermediate nuclear axis.
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| 5. |
- Petrache, C. M., et al.
(author)
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Evidence of chiral bands in even-even nuclei
- 2018
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In: Physical Review C. - : American Physical Society. - 2469-9985 .- 2469-9993. ; 97:4
-
Journal article (peer-reviewed)abstract
- Evidence for chiral doublet bands has been observed for the first time in the even-even nucleus Nd136. One chiral band was firmly established. Four other candidates for chiral bands were also identified, which can contribute to the realization of the multiple pairs of chiral doublet bands (MχD) phenomenon. The observed bands are investigated by the constrained and tilted axis cranking covariant density functional theory (TAC-CDFT). Possible configurations have been explored. The experimental energy spectra, angular momenta, and B(M1)/B(E2) values for the assigned configurations are globally reproduced by TAC-CDFT. Calculated results support the chiral interpretation of the observed bands, which correspond to shapes with maximum triaxiality induced by different multiquasiparticle configurations in Nd136.
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| 6. |
- Lv, B. F., et al.
(author)
-
Chirality of Nd-135 reexamined : Evidence for multiple chiral doublet bands
- 2019
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In: Physical Review C. - : American Physical Society. - 2469-9985 .- 2469-9993. ; 100:2
-
Journal article (peer-reviewed)abstract
- One new pair of positive-parity chiral doublet bands have been identified in the odd-A nucleus Nd-135 which together with the previously reported negative-parity chiral doublet bands constitute a third case of multiple chiral doublet (M chi D) bands in the A approximate to 130 mass region. The properties of the M chi D bands are well reproduced by constrained covariant density functional theory and particle rotor model calculations. The newly observed M chi D bands in Nd-135 represents an important milestone in supporting the existence of M chi D in nuclei.
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| 7. |
- Petrache, C. M., et al.
(author)
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Collective rotation of an oblate nucleus at very high spin
- 2019
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In: Physical Review C. - : American Physical Society (APS). - 2469-9985 .- 2469-9993. ; 99:4
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Journal article (peer-reviewed)abstract
- A sequence of nine almost equidistant quadrupole transitions is observed in Nd137. The sequence represents an extremely regular rotational band that extends to a spin of about 75/2 and an excitation energy of ≈4.5MeV above yrast. Cranked mean-field calculations of the Nilsson-Strutinsky type suggest an oblate shape for the band. They reproduce the observed I(I+1) dependence of the rotational energy whereas predicting a pronounced decrease in the deformation, which is the hallmark of antimagnetic rotation.
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| 8. |
- Petrache, C. M., et al.
(author)
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Highly deformed bands in Nd nuclei : New results and consistent interpretation within the cranked Nilsson-Strutinsky formalism
- 2019
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In: Physical Review C. - : American Physical Society (APS). - 2469-9985 .- 2469-9993. ; 100:5
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Journal article (peer-reviewed)abstract
- Three new highly-deformed (HD) bands are identified in Nd136 and the highly deformed band of Nd137 is extended at higher spin by four transitions, revealing a band crossing associated with the occupation of the second νi13/2 intruder orbital. Extended cranked Nilsson-Strutinsky calculations are performed for all HD bands observed in Nd134, Nd136, and Nd137, achieving for the first time a consistent interpretation of all HD bands in the Nd nuclei. The new interpretation has significant consequences, like the change of parity of the yrast HD bands of Nd134 and Nd136, and the involvement of two negative-parity neutron intruder orbitals in the configurations of most HD bands. The present experimental results and their theoretical interpretation represent an important step forward in the understanding of the second-minimum excitations in the Nd nuclei.
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| 9. |
- Petrache, C. M., et al.
(author)
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Multiple chiral bands in 137 Nd
- 2020
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In: European Physical Journal A. - : Springer Nature. - 1434-6001 .- 1434-601X. ; 56:8
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Journal article (peer-reviewed)abstract
- Two new bands have been identified in 137Nd from a high-statistics JUROGAM II gamma-ray spectroscopy experiment. Constrained density functional theory and particle rotor model calculations are used to assign configurations and investigate the band properties, which are well described and understood. It is demonstrated that these two new bands can be interpreted as chiral partners of previously known three-quasiparticle positive- and negative-parity bands. The newly observed chiral doublet bands in 137Nd represent an important support to the existence of multiple chiral bands in nuclei. The present results constitute the missing stone in the series of Nd nuclei showing multiple chiral bands, which becomes the most extended sequence of odd–even and even-even nuclei presenting multiple chiral bands in the Segré chart.
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| 10. |
- Petrache, C. M., et al.
(author)
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Signatures of enhanced octupole correlations at high spin in Nd 136
- 2020
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In: Physical Review C. - : American Physical Society (APS). - 2469-9985 .- 2469-9993. ; 102:1
-
Journal article (peer-reviewed)abstract
- Experimental signatures of moderately enhanced octupole correlations at high spin in Nd136 are indicated for the first time. The extracted dipole moments of two negative-parity bands are only two times smaller than those of the lanthanide nuclei with N≈90 which present well-established octupole correlations. Calculations using the cranked quasiparticle random phase approximation and a model of quadrupole-octupole rotations with octupole vibrations reveal the structure of the bands and the enhanced octupole correlations at high spin in Nd136.
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