| 1. |
- Jensen, DR, et al.
(författare)
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Coexisting wobbling and quasiparticle excitations in the triaxial potential well of Lu-163
- 2004
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Ingår i: European Physical Journal A. Hadrons and Nuclei. - : Springer Science and Business Media LLC. - 1434-6001. ; 19:2, s. 173-185
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Tidskriftsartikel (refereegranskat)abstract
- High-spin states of the nucleus Lu-163 have been populated through the fusion-evaporation reaction La-139(Si-29, 5n) with a beam energy of 157 MeV. In addition to the two lowest excited triaxial strongly deformed (TSD) bands, recently interpreted as one- and two-phonon wobbling excitations, a third excited TSD band has been firmly established decaying to the yrast TSD band. The assignment of this band as a three-quasiparticle band shows together with the normal deformed (ND) level scheme the presence not only of shape coexistence between ND and TSD structures, but also an interplay of wobbling and quasiparticle excitations in the triaxial strongly deformed potential well of Lu-163.
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| 2. |
- Neusser, A, et al.
(författare)
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Superdeformed band at very high spin in Nd-140
- 2004
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 70:6
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Tidskriftsartikel (refereegranskat)abstract
- A new high-spin superdeformed band has been discovered in Nd-140(60)80. It was populated in the Zr-96(Ca-48,4n) reaction and investigated using the EUROBALL gamma-ray spectrometer array. The band is observed in the approximate spin range of I=36 to 66. It is associated with shell gaps around Z=60 and at N=80 at large deformation. These gaps produce a pronounced minimum in the calculated total Routhian surfaces at a quadrupole deformation of epsilon(2)=0.45. The new band which lies between the high-deformation bands in the Aapproximate to130 region and the superdeformed bands in Aapproximate to150 nuclei provides insight into the development of the deformation between these two regions. Two possible configurations are suggested involving four neutrons of i(13/2) origin (nu6(4)) and either six protons of h(11/2)/h(9/2) origin (pi5(6)) or five protons of h(11/2)/h(9/2) and one of i(13/2) origin (pi5(5)6(1)).
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| 3. |
- Petrache, C. M., et al.
(författare)
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Stable triaxiality at the highest spins in 138Nd and 139Nd
- 2000
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Ingår i: Physical Review C - Nuclear Physics. - 0556-2813. ; 61:1, s. 113051-113055
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Tidskriftsartikel (refereegranskat)abstract
- The nuclei 138Nd and 139Nd have been studied at very high spins via the 48Ca+94Zr reaction. Several new rotational bands were observed, four in 138Nd and two in 139Nd. The J(2) moments of inertia calculated from the observed γ-ray energies are very small and almost constant, indicating that these bands are triaxial. Cranked Nilsson-Strutinsky calculations reproduce the general behavior of the bands, supporting this interpretation and suggesting an approximately constant γ value of ∼ + 35° over a large spin range up to the highest observed spins. These bands and a few similar bands in other nuclei of the N≈80 region are a unique example of almost undisturbed triaxial bands.
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| 4. |
- Schonwasser, G, et al.
(författare)
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Coexisting normal and triaxial superdeformed structures in Lu-165
- 2004
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Ingår i: Nuclear Physics, Section A. - : Elsevier BV. - 0375-9474. ; 735:3-4, s. 393-424
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Tidskriftsartikel (refereegranskat)abstract
- High-spin states in Lu-165 were populated in the La-139(Si-30, 4n) reaction at a beam energy of 152 MeV and gamma-ray coincidences were measured with the EUROBALL spectrometer array. Nine new rotational bands were discovered, known band structures were considerably extended and many inter-band transitions were found. Structures with normal deformation coexist with bands associated with the strongly deformed triaxial energy minima found in calculations. Three of these triaxial bands form a family of wobbling excitations with phonon quanta n(w) = 0, 1 and 2. The wobbling mode is a unique signature of nuclear triaxiality. Configuration assignments are discussed for the observed band structures. An exchange of configuration between two of the new bands due to mixing is observed, resulting in different signature partnerships at low and high spins.
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| 5. |
- Schonwasser, G, et al.
(författare)
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One- and two-phonon wobbling excitations in triaxial Lu-165
- 2003
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Ingår i: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - 0370-2693. ; 552:1-2, s. 9-16
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Tidskriftsartikel (refereegranskat)abstract
- High-spin states in Lu-165 have been investigated by in-beam gamma-ray coincidence spectroscopy using the EUROBALL spectrometer array. Two new excited rotational bands have been discovered with features similar to a previously known triaxial superdeformed band in that nucleus. Comparison of the decay pattern of these bands, in particular the unusually large E2 transition strength from the first excited to the yrast superdeformed band, to theoretical calculations shows that they belong to a family of wobbling excitations with phonon numbers n(w) = 0, 1 and 2. These results, together with evidence for nuclear wobbling in the neighbouring isotopes Lu-163 and Lu-167, firmly establish this mode of excitation in the A = 165 mass region. The observation of wobbling is a unique signature of stable nuclear triaxiality. (C) 2002 Elsevier Science B.V. All rights reserved.
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| 6. |
- Lunardi, S, et al.
(författare)
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Highly deformed band in Nd-138
- 2004
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 69:5
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Tidskriftsartikel (refereegranskat)abstract
- High-spin states in Nd-138 have been investigated with the reaction Zr-94(Ca-48,4n), using the GASP array. A new rotational band has been identified, which has close similarities with the well known highly deformed bands of the lighter Nd isotopes, and is therefore interpreted as built on the second minimum of the nuclear potential energy surface. From comparison with calculations a configuration is suggested which involves two neutrons in the i(13/2) deformation driving orbital.
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| 7. |
- Bracco, A, et al.
(författare)
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Search for the GDR built on superdeformed nuclei
- 2000
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Ingår i: PHYSICA SCRIPTA. - : ROYAL SWEDISH ACAD SCIENCES. - 0281-1847. ; T88, s. 182-188
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Tidskriftsartikel (refereegranskat)abstract
- An experiment aiming at finding evidence for gamma-decay of the giant dipole resonance built on superdeformed nuclear states has been made using the EUROBALL gamma-detector array coupled to the large BaF2 detectors of the HECTOR system. The reaction Pd-11
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