| 1. |
- Mason, P, et al.
(författare)
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Octupole signatures in Ba-124,Ba-125
- 2005
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Ingår i: Journal of Physics G. - : IOP Publishing. - 0954-3899 .- 1361-6471. ; 31:10, s. S1729-S1733
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Tidskriftsartikel (refereegranskat)abstract
- The gamma decay of the nuclei Ba-121,Ba-125 has been investigated with the EUROBALL array, using the reaction Ni-64+Ni-64 at E-beam = 255 and 261 MeV. Six new E1 transitions have been found in the nucleus Ba-125, suggesting a significant role of octupole correlations in the origin of its parity doublets. The J(pi) = 3(-) level of the nucleus Ba-124 has been identified for the first time. Its excitation energy is in very good agreement with a prediction based on a microscopic model including octupole interactions.
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| 2. |
- Yadav, R. B., et al.
(författare)
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Identification of triaxial strongly deformed bands in Hf-168
- 2008
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 78:4
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Tidskriftsartikel (refereegranskat)abstract
- Possible decay pathways associated with three candidates for triaxial strongly deformed (TSD) bands in Hf-168 have been investigated. The spin and excitation energy of the strongest band, TSD1, were determined approximately based on gamma-ray coincidence relationships. Discrete links were established for the second band. The overall agreement between the observed properties of the bands and cranking calculations using the ULTIMATE CRANKER code provides strong support for an interpretation where band TSD1 is associated with a TSD minimum, (epsilon(2),gamma)similar to(0.43,20(degrees)), involving the pi(i(13/2))(2) and the nu(j(15/2)) high-j orbitals. This constitutes the first identification of a TSD band in Hf isotopes, which has been long-predicted by theoretical studies. The second band is understood as being associated with a near-prolate shape and a deformation enhanced with respect to the normal deformed bands. It is proposed to be built on the pi(i(13/2)h(9/2))circle times nu(i(13/2))(2) configuration.
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| 3. |
- Petrache, C. M., et al.
(författare)
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Triaxiality at high spins in Nd nuclei
- 2006
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Ingår i: Physica Scripta. - 0031-8949. ; T125, s. 212-213
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Tidskriftsartikel (refereegranskat)abstract
- The level structure of Nd-140(80) has been established up to spin 48 by in-beam gamma-ray spectroscopy using the Zr-96(Ca-48, 4n) reaction. High-fold gamma-ray coincidences were measured with the EUROBALL spectrometer. Twelve new rotational bands have been discovered at high spins, showing the change from a spherical single-particle behaviour at low spins to a deformed regime with stable triaxiality at high spins. Possible configurations are assigned to the observed bands on the basis of configuration-dependent cranked Nilsson-Strutinsky calculations.
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| 4. |
- Al-Khatib, A, et al.
(författare)
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Transition to non-collective states at high spin in Xe-124
- 2008
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Ingår i: European Physical Journal A. Hadrons and Nuclei. - : Springer Science and Business Media LLC. - 1434-6001. ; 36:1, s. 21-29
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Tidskriftsartikel (refereegranskat)abstract
- Excited states in Xe-124 were populated in the reaction Se-82(Ca-48, 6n) Xe-124 and gamma-ray coincidence relationships were measured with the Gammasphere spectrometer. Two new bands are observed and several of the previously known bands are extended in the high-as well as in the low-spin region. Two irregular high-spin structures are also added. The irregularities are a fingerprint of a transition from collective to non-collective behaviour. Configuration assignments to the new structures are proposed on the basis of systematics and by comparing experimental properties with calculations within the framework of the cranking model.
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| 5. |
- Herskind, B., et al.
(författare)
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Charged particle feeding of hyperdeformed nuclei in the A=118-126 region
- 2006
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Ingår i: Physica Scripta. - 0031-8949 .- 1402-4896. ; T125, s. 108-114
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Tidskriftsartikel (refereegranskat)abstract
- A breakthrough was recently obtained in the analysis of the so-called Hyper-Long-HyperDeformed (HLHD) experiment made at the EUROBALL-IV gamma-detector array (EB). The Ni-64 + Ni-64 double right arrow Ba-128* fusion reaction was studied at E-beam = 255 and 261 MeV, reaching the highest angular momentum that the compound nuclei can accommodate. To date no discrete HD rotational bands have been identified. However, rotational patterns in the form of ridge-structures in three-dimensional (3D) rotational mapped spectra are identified with dynamic moments of inertia J((2)) ranging from 71 to 111h(2) MeV-1 in 12 different nuclei selected by charged particle- and/or gamma-gating. The four nuclei, Te-118, Cs-124, Cs-125 and Xe-124 found with moment of inertia J((2)) >= 100h(2) MeV-1, are most likely hyperdeformed, the remaining nuclei with smaller values of J((2)), are considered to be superdeformed, in qualitative agreement with recent theoretical calculations.
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| 6. |
- Herskind, B., et al.
(författare)
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Light charged particles as gateway to hyperdeformation
- 2007
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Ingår i: Acta Physica Polonica B. - 0587-4254 .- 1509-5770. ; 38:4, s. 1421-1430
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Tidskriftsartikel (refereegranskat)abstract
- The Euroball-IV gamma-detector array, equipped with the ancillary charged particle detector array DIAMANT was used to study the residues of the fusion reaction Ni-64 + Ni-64 double right arrow Ba-128 at E-beam. = 255 and 261 MeV, in an attempt to reach the highest angular momentum and verify the existence of predicted hyperdeformed rotational bands. No discrete hyperdeformed bands were identified, but nevertheless a breakthrough was obtained through a systematic search for rotational ridge structures with very large moments of inertia J(2) >= 100 h(2) MeV((-1)), in agreement with theoretical predictions for hyperdeformed shapes. Evidence for hyperdeformation was obtained by charged particle + gamma-ray gating, selecting triple correlated ridge structures in the continuum of each of the nuclei, Te-118, Xe-124 and Cs-124,Cs-125. In 7 additional nuclei, rotational ridges were also identified with J(2) = 71-77h(2) MeV((-1)), which most probably correspond to superdeformed shape. The angular distributions of the emitted charged particles show an excess in forward direction over expectations from pure compound evaporation, which may indicate that in-complete fusion plays an important role in the population of very elongated shapes.
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