| 1. |
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| 2. |
- Ideguchi, E., et al.
(författare)
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Orbifold projection in supersymmetric QCD at N(f) ≤ N(c)
- 2000
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Ingår i: Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics. - 0370-2693. ; 492:3-4, s. 369-375
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Tidskriftsartikel (refereegranskat)abstract
- Supersymmetric orbifold projection of N = 1 SQCD with relatively small number of flavors (N(f) ≤ N(c)) is considered. The purpose is to check whether orbifolding commutes with the infrared limit. On the one hand, one considers the orbifold projection of SQCD and obtains the low-energy description of the resulting theory. On the other hand, one starts with the low-energy effective theory of the original SQCD, and only then performs orbifolding. It is shown that at finite N(c) the two low-energy theories obtained in these ways are different. However, in the case of stabilized run-away vacuum these two theories are shown to coincide in the large N(c) limit. In the case of quantum modified moduli space, topological solitons carrying baryonic charges are present in the orbifolded low-energy theory. These solitons may restore the correspondence between the two theories provided that the soliton mass tends to zero in the large N(c) limit. (C) 2000 Elsevier Science B.V.
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| 3. |
- Pfohl, J., et al.
(författare)
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Highly deformed rotational structures in 136Pm
- 2000
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Ingår i: Physical Review C - Nuclear Physics. - 0556-2813. ; 62:3, s. 313041-313045
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Tidskriftsartikel (refereegranskat)abstract
- Four highly deformed structures in the odd-odd nucleus 13661Pm75 were observed via the 105Pd(35Cl,2p2n) reaction at 180 and 173 MeV using the GAMMASPHERE γ-ray spectrometer and the Microball charged-particle detector array. Quadrupole moment measurements were performed on all of the bands. In contrast to lighter odd-Ζ Pm and Pr nuclei, bands based on the g9/2[404]9/2 proton orbital were not observed. Instead, the four observed sequences are assigned as a coupling of an i13/2 neutron with the low-Ω h11/2 and mixed d5/2g7/2 orbitals. Comparisons with neighboring highly deformed structures are discussed and cranked Nilsson-Strutinsky calculations for 136Pm are presented.
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| 4. |
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| 5. |
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| 6. |
- Jonsson, K, et al.
(författare)
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Collective excitations and band termination in Nb-85
- 1999
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Ingår i: Nuclear Physics A. - 0375-9474 .- 1873-1554. ; 645:1, s. 47-60
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Tidskriftsartikel (refereegranskat)abstract
- High-spin states in Nb-85 were studied using the GAMMASPHERE Ge detector array and the MICROBALL charged-particle detector system. Three gamma-ray cascades with collective rotational characteristics were observed. One of the bands exhibits a forking at the top, most likely reflecting the termination of one branch into a favoured non-collective, near spherical state. The data are interpreted in terms of cranked Strutinsky-type calculations.
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| 7. |
- Devlin, M., et al.
(författare)
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Superdeformation in 68Zn: Evidence for a New, Neutron-rich Island of Superdeformation in A~70 Nuclei
- 1999
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Ingår i: Physical Review Letters. - 1079-7114. ; 82, s. 5217-5220
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Tidskriftsartikel (refereegranskat)abstract
- A superdeformed rotational structure is reported in the stable nucleus Zn-68. It has a transition quadrupole moment (Q(t)) of 2.5(-0.4)(+0.7) e b (beta(2) approximate to 0.4), as measured by the residual Doppler shift method. Theoretical calculations suggest that two different configurations are possible candidates for this band. One is built without h(11/2) neutrons, as seen in superdeformed bands in the A similar to 60 region, while the other involves one h(11/2) neutron in analogy with superdeformed bands in the A similar to 80 region. The second of these candidate configurations is preferred, thus establishing a new, neutron-rich (relative to the line of beta stability) region of superdeformation with Z similar to 30 and N similar to 38.
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| 8. |
- LaFosse, D R, et al.
(författare)
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Search for hyperdeformation in Gd-146,Gd-147
- 1996
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Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 54:4, s. 1585-1588
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Tidskriftsartikel (refereegranskat)abstract
- A search was undertaken to look for evidence of hyperdeformation in Gd-146,Gd-147. Three experiments employing Gammasphere for gamma-ray detection coupled with the Microball for channel selection via charged particle detection were carried out with increasing detection sensitivity and statistics. No definitive evidence for band structures that could be assigned to hyperdeformation could be found. Candidates previously reported are shown not to have properties consistent with a band structure.
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| 9. |
- Naguleswaran, S., et al.
(författare)
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Magnetic and intruder rotational bands in In-113
- 2005
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Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 72:4, s. 044304-
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Tidskriftsartikel (refereegranskat)abstract
- Excited states in In-113 were populated via the reactions Mo-100(O-18,p4n)In-113 and Pd-110(Li-7,4n)In-113. The two known Delta J=2 intruder bands, based on the pi g(7/2)circle times d(5/2) and pi h(11/2) orbitals, have been extended by 8h to spins (49/2(+))h and (55/2(-))h, respectively. The previous finding of three sequences of Delta J=1 gamma-ray transitions has been confirmed. A self-consistent cranked shell-model calculation gives a good description of the contrasting alignment patterns of the two Delta J=2 intruder bands. The intruder bands, the known sequences of M1 transitions, and spherical levels together represent a coexistence of three different excitation modes in this nucleus.
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| 10. |
- Smith, J. F., et al.
(författare)
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Excited states and signature inversion in Cs-116
- 2006
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Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 74:3, s. 034310-
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Tidskriftsartikel (refereegranskat)abstract
- Excited states have been observed for the first time in the very neutron-deficient, odd-odd nucleus, Cs-116(55)61. The assignment to Cs-116 has been made by the detection of gamma rays in coincidence with evaporated charged particles and with evaporation residues. The observed states form a rotational band which has been assigned to the nu(h(11/2)) circle times pi(h(11/2)) configuration. Tentative spin assignments have been made on the basis of systematic comparisons with neighboring cesium isotopes. A low-spin signature inversion is observed in the band at a rotational frequency of about 0.23 MeV/h. The observed signature inversions in the odd-odd Cs116-126 isotopes have been compared with the results of extended total Routhian surface calculations, in which signature inversion arises as a consequence of quadrupole-pairing correlations and triaxial deformation. As previously shown for some of the odd-odd A similar or equal to 120 isotopes, the calculations reproduce the signature inversions reasonably well.
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| 11. |
- Wilson, A. N., et al.
(författare)
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High-spin structures and alignment properties in Ce-126
- 2001
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Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 6305:5
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Tidskriftsartikel (refereegranskat)abstract
- Excited states in Ce-126 have been observed with the GAMMASPHERE gamma -ray detector array, used in conjunction with the MICROBALL charged-particle detector. The reaction Zn-64(Zn-64, xpn alpha) (beam energy 260 MeV) was used to populate a wide range of nuclei in the neutron-deficient region with A approximate to 120. Ce-126 was populated via the 2p evaporation channel. The three previously observed bands have been extended to higher spins and some other structures have been identified. The yrast band shows evidence of a delayed neutron alignment occurring at a rotational frequency omega approximate to0.5 MeV/(h) over bar as observed in the neighboring odd-A nucleus Pr-127. One of the two excited bands shows evidence for a similar crossing at a slightly lower frequency and also exhibits a sudden gain in alignment at omega =0.57 MeV/(h) over bar. The third band may involve the coupling of a gamma -vibrational state. All three rotational bands are discussed in terms of standard and extended cranked shell model calculations.
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| 12. |
- Chiara, C. J., et al.
(författare)
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Probing sd-fp Cross-shell Interactions via Terminating Configurations in 42Sc,43Sc
- 2007
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 75:5
-
Tidskriftsartikel (refereegranskat)abstract
- An experimental study of the lower fp-shell nuclei Sc-42,Sc-43 was performed via alpha pn and alpha p evaporation, respectively, from Ne-20 + Si-28 and Mg-24 + Mg-24 fusion-evaporation reactions. The experiments were conducted with the Gammasphere and Microball detector arrays. The level schemes of both nuclei have been extended considerably. Terminating states associated with the f(7/2)(n) and d(3/2)(-1)f(7/2)(n+1) configurations were identified in each nuclide and incorporated into detailed comparisons with neighboring nuclei and with shell model calculations. The energy differences between the terminating states provide a test of the sd-fp cross-shell interactions in these calculations.
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| 13. |
- Gellanki, Jnaneswari, et al.
(författare)
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Characterization of Superdeformed Bands in 62Zn
- 2009
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 80:5
-
Tidskriftsartikel (refereegranskat)abstract
- Combined data from four fusion-evaporation reaction experiments were utilized to investigate deformed and superdeformed structures in Zn-62(30)32. Combination of the Gammasphere gamma-ray spectrometer and ancillary particle detection systems allowed for the connection of rotational bands to well-known, low-lying excited states in Zn-62, as well as spectroscopy of discrete high-spin states reaching excitation energies of E-x=42.5 MeV. Four well- or superdeformed bands in Zn-62 are characterized and described by means of cranked Nilsson-Strutinsky calculations.
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| 14. |
- Ideguchi, Eiji, et al.
(författare)
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Superdeformation in 91Tc
- 2000
-
Ingår i: Physics Letters B. - : Elsevier. - 0370-2693 .- 1873-2445. ; 492:3-4, s. 245-253
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Tidskriftsartikel (refereegranskat)abstract
- A high-spin rotational band with 11 gamma -ray transitions has barn observed in Tc-91. The dynamical moment of inertia as well as the transition quadrupole moment of 8.1(-1.4)(+1.9) eb measured for this band show the characteristics of a superdeformed band. However, the shape is more elongated than in the neighbouring A = 80-90 superdeformed nuclei. Theoretical interpretations of the band within the cranked Strutinsky approach based on two different Woods-Saxon potential parameterisations are presented. Even though an unambiguous configuration assignment proved difficult, both calculations indicate a larger deformation and at least three additional high-N intruder orbitals occupied compared to the lighter SD nuclei. (C) 2000 Elsevier Science B.V. All rights reserved.
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| 15. |
- Ideguchi, E., et al.
(författare)
-
Superdeformation in the Doubly Magic Nucleus 40Ca
- 2001
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Ingår i: Physical Review Letters. - 1079-7114. ; 87:22
-
Tidskriftsartikel (refereegranskat)abstract
- A rotational band with seven gamma -ray transitions between states with spin 2 (h) over bar and 16 (h) over bar has been observed in the doubly magic, self-conjugate nucleus Ca-40(20)20. The measured transition quadrupole moment of 1.80(-0.29)(+0.39)eb indicates a superdeformed shape with a deformation beta (2) = 0.59(-0.07)(+0.11). The features of this band are explained by cranked relativistic mean field calculations to arise from an 8-particle 8-hole excitation.
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| 16. |
- Lerma, F., et al.
(författare)
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Superdeformed bands in Sr80-83, Y82-84, Zr-83,Zr-84 : Transition quadrupole moments, moments of inertia, and configuration assignments
- 2003
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Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 67:4, s. 044310-
-
Tidskriftsartikel (refereegranskat)abstract
- Multiple superdeformed bands in the nuclei Sr80-83, Y82-84, and Zr-83,Zr-84 have been studied in a backed-target experiment, using the Gammasphere and the Microball 4pi detector arrays. For 15 bands in these nuclei, average transition quadrupole moments have been measured with high accuracy, using the Doppler-shift attenuation method. Among these are the newly observed superdeformed bands in Y-83,Y-84, which are isospectral with the bands in Sr-82,Sr-83. These isospectral bands have nearly identical transition quadrupole moments. Two of the bands in Sr-81 interact and cross transitions between them are observed. The present measurements place stringent conditions on configuration assignments for the bands obtained from two types of mean-field calculations, leading to a consistent understanding of the mass similar to80 superdeformed bands. The assignments for different bands arise from one or more nucleons occupying the N-0=5h(11/2) intruder orbital.
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| 17. |
- Sarantites, D. G., et al.
(författare)
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Triaxial superdeformed bands in [Formula Presented]
- 1998
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Ingår i: Physical Review C - Nuclear Physics. - 0556-2813. ; 57:1, s. 1-5
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Tidskriftsartikel (refereegranskat)abstract
- Four new superdeformed bands have been found in the nucleus [Formula Presented]. The good agreement between experiment and configuration-dependent shell correction calculations suggests that three of the bands have triaxial superdeformed shapes. Such unique features in mass [Formula Presented] superdeformed bands have been predicted, but not observed experimentally until now. A fourth band in [Formula Presented] is interesting due to a fairly constant and unusually high dynamic moment of inertia. Possible interpretations of this structure are discussed.
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| 18. |
- Sun, H., et al.
(författare)
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New Band Structures and an Unpaired Crossing in 78Kr
- 1999
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 59:2, s. 655-664
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Tidskriftsartikel (refereegranskat)abstract
- High-spin states in Kr-78 were studied using the Ni-58(Na-23,3p) reaction at 70 MeV and the Ni-58(Si-23,alpha 4p) reaction at 130 MeV. Prompt gamma-gamma coincidences were measured using the Pitt-FSU detector array and the GAMMASPHERE-MICROBALL array. Results from these experiments have led to 26 new excitation levels, some of which have been grouped into 3 new bands. Spins were assigned based on directional correlations of oriented nuclei. Two of the new negative-parity bands appear to form a signature-partner pair based on a two-quasineutron structure, in contrast to the previously known two-quasiproton negative-parity bands. A forking has been observed at the 24(+) state in the yrast band, which calculations suggest may result from an unpaired crossing. The available evidence suggests oblate shapes in the yrast band coexist with prolate shapes in the negative-parity bands. [S0556-2813(99)04602-6].
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| 19. |
- Svensson, C. E., et al.
(författare)
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Decay Out of the Doubly Magic Superdeformed Band in the N=Z Nucleus 60Zn
- 1999
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Ingår i: Physical Review Letters. - 1079-7114. ; 82:17, s. 3400-3403
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Tidskriftsartikel (refereegranskat)abstract
- The doubly magic superdeformed band in the N = Z nucleus Zn-60 has been identified. Linking transitions connecting this band to the yrast line provide the first spin, parity, and excitation energy measurements for superdeformed states in the A similar to 60 region. The stretched-E2 character and relatively large B(E2) values of these transitions suggest a nonstatistical decay-out process.
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| 20. |
- Svensson, C. E., et al.
(författare)
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Observation and Quadrupole Moment Measurement of the First Superdeformed Band in the A~60 Mass Region
- 1997
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Ingår i: Physical Review Letters. - 1079-7114. ; 79:7, s. 1233-1236
-
Tidskriftsartikel (refereegranskat)abstract
- A high-spin rotational cascade of six gamma rays has been observed in Zn-62. The quadrupole moment of 2.7(-0.5)(+0.7) e b measured for this band corresponds to a deformation beta(2) = 0.45(-0.07)(+0.10). The properties of this band are in excellent agreement with calculations that predict high-spin superdeformed bands in Zn-62 with deformations beta(2) = 0.41-0.49. These results establish a new region of superdeformation for nuclei with neutron and proton numbers N, Z approximate to 30-32.
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| 21. |
- Svensson, C. E., et al.
(författare)
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Smooth Termination of Rotational Bands in 62Zn: Evidence for a Loss of Collectivity
- 1998
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Ingår i: Physical Review Letters. - 1079-7114. ; 80:12, s. 2558-2561
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Tidskriftsartikel (refereegranskat)abstract
- Two sets of strongly coupled rotational bands have been identified in Zn-62. These bands have been observed up to the terminating states of their respective configurations. Lifetime measurements indicate that the transition quadrupole moments in these bands decrease as termination is approached. These results establish the first terminating states of rotational bands in the A similar to 60 mass region and confirm the predicted loss of collectivity associated with smooth band termination.
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| 22. |
- Thorslund, I., et al.
(författare)
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Intruder bands in Te114 : Smooth band termination
- 1995
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Ingår i: Physical Review C. - 0556-2813. ; 52:6, s. 2839-2843
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Tidskriftsartikel (refereegranskat)abstract
- The nucleus Te114 has been studied in heavy-ion -ray spectroscopy experiments performed with the early implementation of the GAMMASPHERE multidetector array. Three rotational intruder bands have been observed up to high spins. The yrast band, involving the 4p2h (h11/2)2(g7/2)2(g9/2)-2 proton configuration, reaches I=48Latin small letter h with stroke at an excitation energy of 30.3 MeV, the highest observed spin connected by rays in this mass region. The band properties are interpreted in the framework of smooth band termination.
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| 23. |
- Andersson, T., et al.
(författare)
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High-spin States in the A=39 Mirror Nuclei 39Ca and 39K
- 1999
-
Ingår i: European Physical Journal A. Hadrons and Nuclei. - 1434-6001. ; 6, s. 5-8
-
Tidskriftsartikel (refereegranskat)abstract
- High-spin states of the mass A = 39 mirror pair K-39 and Ca-39 were investigated via the fusion-evaporation reaction Si-28+O-16 at 125 MeV beam energy. The GAMMASPHERE array in conjunction with the 4 pi charged-particle detector array MICROBALL and neutron detectors was used to detect gamma rays in coincidence with evaporated light particles. The results of the first high-spin study of the T-z = -1/2 nucleus Ca-39 are discussed in terms of mirror symmetry and compared to spherical shell-model calculations in the 1d(3/2)-1f(7/2) configuration space.
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| 24. |
- Andreoiu, Corina, et al.
(författare)
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Yrast Superdeformed Band in 59Cu
- 2000
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 62:5, s. 513011-513015
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Tidskriftsartikel (refereegranskat)abstract
- High-spin states in 59Cu were populated using the fusion-evaporation reactions 28Si+40Ca at a beam energy of 125 MeV and 36Ar+28Si at a beam energy of 143 MeV. The Gammasphere array in conjunction with ancillary detector systems allowed for the identification of a superdeformed rotational band in 59Cu, which was firmly linked to low-spin yrast states. Using directional correlations of oriented states, a spin-parity assignment of Iπ = 25/2+ to the band head was possible. The average quadrupole moment of the band is measured to be Qt = (2.24±0.40) e b. The characteristics of the band are compared to neighboring nuclei and predictions of different mean-field theories.
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| 25. |
- Bäck, Torbjörn, et al.
(författare)
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Observation of superdeformed states in Mo-88
- 1999
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Ingår i: European Physical Journal A. - New York : SPRINGER VERLAG. - 1434-6001 .- 1434-601X. ; 6:4, s. 391-397
-
Tidskriftsartikel (refereegranskat)abstract
- High-spin states in Mo-88 were studied using the GAMMASPHERE germanium detector array in conjunction with the MICROBALL CsI(TI) charged-particle detector system. Three gamma-ray cascades with dynamic moments of inertia showing similar characteristics to superdeformed rotational bands observed in the neighbouring A = 80 region have been identified and assigned to the nucleus Mo-88. The quadrupole moment of the strongest band, deduced by the Residual Doppler Shift Method, corresponds to a quadrupole deformation of beta(2) approximate to 0.6. This confirms the superdeformed nature of this band. The experimental data are interpreted in the framework of total routhian surface calculations. All three hands are assigned to two-quasi-particle proton configurations at superdeformed shape.
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| 26. |
- Cederwall, Bo, et al.
(författare)
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Favoured superdeformed states in 89TC
- 1999
-
Ingår i: European Physical Journal A. - New York : Springer-Verlag New York. - 1434-6001 .- 1434-601X. ; 6:3, s. 251-255
-
Tidskriftsartikel (refereegranskat)abstract
- A superdeformed band consisting of a cascade of ten gamma-ray transitions has been identified and assigned to the nucleus Tc-89, close to the proton dripline. The quadrupole moment of the band (Q(t) = 6.7(-2.3)(+3.0) eb, as measured by the Residual Doppler Shift Method) as well as a large dynamic moment of inertia point to a highly elongated shape. With a relative population of approximately 15% of the gamma-ray flux in the Tc-89 exit channel, thp band is among the most intense superdeformed bands observed to date.
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| 27. |
- Devlin, M., et al.
(författare)
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Yrast Spectroscopy of 54Cr
- 2000
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 61:1
-
Tidskriftsartikel (refereegranskat)abstract
- High-spin levels in the heaviest stable isotope of chromium were observed following the fusion-evaporation reaction C-12(Ca-48, alpha 2n)Cr-54 at a beam energy of 157 MeV, using the GAMMASPHERE and MICROBALL detector arrays. Numerous yrast and near yrast levels are reported, and previously assigned 7(+) and 9(+) levels are suggested to be 5(+) and 7(+), respectively. The inferred level scheme is compared with shell model calculations.
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| 28. |
- Döring, J., et al.
(författare)
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Band terminations in the valence space of 86Zr
- 2000
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Ingår i: Physical Review C - Nuclear Physics. - 0556-2813. ; 61:3, s. 343101-343106
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Tidskriftsartikel (refereegranskat)abstract
- High-spin states in 86Zr up to 30+ and 27- were observed via the 58Ni(32S,4p) reaction at 135 MeV beam energy using the combined GAMMASPHERE and MICROBALL systems. Calculations performed with the configuration-dependent shell-correction approach show that these states are built from six g9/2 neutrons and at most four protons excited from the p1/2,p3/2,f5/2 subshells to the g9/2 subshell at small deformation. The highest observed states at 27- and 30+ are interpreted as band-terminating states with the latter having the highest spin available in the valence space for 86Zr.
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| 29. |
- Evans, A. O., et al.
(författare)
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Magnetic properties of deformed dipole bands in Te-110,Te-112
- 2006
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Ingår i: Physica Scripta. - 0031-8949. ; T125, s. 192-193
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Tidskriftsartikel (refereegranskat)abstract
- A lifetime analysis using the Doppler-shift attenuation method has been performed on the Tellurium isotopes Te-110,Te-112. The experiment was performed using the Gammasphere array in conjunction with the MICROBALL charged-particle detector. Three strongly coupled bands were previously established in Te-110,Te-112 which were observed up to unusually high spins. In the current experiment, it has been possible to extract lifetime measurements using a Doppler broadened lineshape analysis on one of the Delta I = 1 band structures in Te-110. In contrast to similar Delta I = 1 structures in other nuclei in this mass region, the extracted B(M1) values did not rapidly decrease with increasing angular momentum. Instead, the strongly coupled band in Te-110 represents a deformed 1p-1h structure, rather than a weakly deformed structure showing the shears mechanism.
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| 30. |
- LaFosse, D. R., et al.
(författare)
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Collective structures and band termination in 107Sb
- 2000
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Ingår i: Physical Review C - Nuclear Physics. - 0556-2813. ; 62:1
-
Tidskriftsartikel (refereegranskat)abstract
- High-spin states in the near proton-dripline nucleus 107Sb have been identified, and collectivity in this nucleus has been observed for the first time in the form of two rotational bands. One of the observed rotational structures is a ΔI = 1 band, and is interpreted as based on a π(g9/2)-1 ⊗ π(g7/2d5/2)2 proton configuration. A second structure has ΔI = 2 character, and is explained as being based on a πh11/2⊗[π(g9/2)-2 ⊗ π(g7/2d5/2)2] proton configuration through comparison with cranked Nilsson-Strutinsky model calculations. The calculations predict that this band terminates at a spin of 79/2 (Latin small letter h with stroke).
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| 31. |
- Paul, E. S., et al.
(författare)
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Smooth terminating bands in Te-112: Particle-hole induced collectivity
- 2007
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 75:1
-
Tidskriftsartikel (refereegranskat)abstract
- The Gammasphere spectrometer, in conjunction with the Microball charged-particle array, was used to investigate high-spin states in Te-112 via Ni-58(Ni-58, 4p gamma) reactions at 240 and 250 MeV. Several smooth terminating bands were established, and lifetime measurements were performed for the strongest one using the Doppler-shift attenuation method. Results obtained in the spin range 18-32h yield a transition quadrupole moment of 4.0 +/- 0.5eb, which corresponds to a quadrupole deformation epsilon(2)=0.26 +/- 0.03; this value is significantly larger than the ground-state deformation of tellurium isotopes. It was also possible to extract a transition quadrupole moment for the yrast band in Xe-114, produced via the 58Ni (58Ni, 2p gamma) reaction. A value of 3.0 +/- 0.5eb was found in the spin range 16-24h, which corresponds to a quadrupole deformation epsilon(2)=0.19 +/- 0.03. Cranked Nilsson-Strutinsky calculations are used to interpret the results.
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| 32. |
- Robinson, SD, et al.
(författare)
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High-spin structures and band termination effects in Cd-104
- 2002
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Ingår i: Journal of Physics G: Nuclear and Particle Physics. - : IOP Publishing. - 0954-3899. ; 28:6, s. 1415-1431
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Tidskriftsartikel (refereegranskat)abstract
- High-spin states in the neutron-deficient isotope Cd-104 were populated using the Cr-50(Ni-58,4p)Cd-104 reaction at a beam energy of 250 MeV The level scheme has been extended using triple gamma-ray coincidences to a spin of 29h and an excitation energy of 18.2 MeV. Several collective structures involving the excitation of h(11/2) neutrons have been observed to spins approaching 30h. The high-spin structure has been compared to the results of cranked Nilsson-Strutinsky calculations.
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| 33. |
- Rudolph, Dirk, et al.
(författare)
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High-spin Shell-model States Near 56Ni
- 1999
-
Ingår i: European Physical Journal A. Hadrons and Nuclei. - 1434-6001. ; 4:2, s. 115-145
-
Tidskriftsartikel (refereegranskat)abstract
- High-spin states of nuclei near doubly magic Ni-56 were studied with the reaction Si-28(Ar-36, xpynz alpha) at 136 MeV beam energy. The GAMMASPHERE array in conjunction with the 4 pi charged-particle detector array MICROBALL and neutron detectors were used to detect gamma rays in coincidence with evaporated light particles. The resulting extensive decay schemes of Fe-54, Co-54,Co-55, Ni-56,Ni-57, and Cu-58 are compared to shell model calculations in the fp shell.
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| 34. |
- Rudolph, Dirk, et al.
(författare)
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Prompt Alpha Decay of a Well-deformed Band in 58Ni
- 2001
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Ingår i: Physical Review Letters. - 1079-7114. ; 86, s. 1450-1453
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Tidskriftsartikel (refereegranskat)abstract
- Two excited well-deformed bands have been observed in the semi-magic nucleus Ni-58. One of the bands was observed to partially decay by emission of a prompt discrete alpha particle that feeds the 2949 keV 6(+) spherical yrast state in the daughter nucleus Fe-54. This constitutes the first observation of prompt alpha emission from states lying in the deformed secondary minimum of the nuclear potential. gamma -ray linking transitions via several parallel paths establish the spin. parity, and excitation energy of this deformed band in Ni-58.
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| 35. |
- Rudolph, Dirk, et al.
(författare)
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Rotational Bands in the Doubly Magic Nucleus 56Ni
- 1999
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Ingår i: Physical Review Letters. - 1079-7114. ; 82:19, s. 3763-3766
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Tidskriftsartikel (refereegranskat)abstract
- Structures of the medium- to high-spin states in the doubly magic nucleus Ni-56 have been investigated using the reaction Si-28(Ar-36, 2 alpha) and the gamma-ray spectrometer Gammasphere in conjunction with the 4 pi charged-particle detector array Microball. Two well-deformed rotational bands have been identified. There is evidence that one of the bands, which is identical to a sequence in the odd-odd neighbor Cu-58, partially decays via proton emission into the ground state of Co-55. Predictions of extensive large-scale shell-model and cranked Hartree-Fock and Hartree-Fock-Bogolyubov calculations are compared with the experimental data.
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| 36. |
- Rudolph, Dirk, et al.
(författare)
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Shell-model Influence in the Rotational Nucleus 86Mo
- 1996
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 54:1, s. 117-124
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Tidskriftsartikel (refereegranskat)abstract
- High-spin states in Mo-86 were studied by means of the fusion evaporation reaction Ni-58(S-32,2p2n) Mo-86 at 135 MeV beam energy. Charged-particle-gamma gamma and -gamma gamma gamma coincidences recorded with the early implementation of the GAMMASPHERE array and the MICROBALL charged-particle detection system were used to largely extend the level scheme of the T-tau=1 nucleus Mo-86 to a possible spin of I=24h at 13 MeV excitation energy. The excitation scheme is compared to neighboring nuclei. There is evidence for enhanced shell-model influence in the 4 quasiparticle region (I=12-16h). The observed (pi=+,alpha=0) sequence at spin I greater than or equal to 16 h appears to be associated with a triaxial collective rotational band. This interpretation is supported by calculations within the configuration-dependent shell-correction approach with the cranked Nilsson potential.
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| 37. |
- Rudolph, Dirk, et al.
(författare)
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Spherical and Deformed High-spin states in 38Ar
- 2002
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 65:3
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Tidskriftsartikel (refereegranskat)abstract
- Excited states in Ar-38 have been investigated by means of the heavy-ion fusion-evaporation reaction Si-28 +O-16. The level scheme reveals a subtle interplay between spherical, deformed, and superdeformed shapes. Large-scale shell-model calculations in the sd-fp space are invoked to study the microscopic aspects of deformation and shape changes.
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| 38. |
- Starosta, K., et al.
(författare)
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Smooth band termination at high spin in 113I
- 2001
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Ingår i: Physical Review C - Nuclear Physics. - 0556-2813. ; 64:1, s. 143041-1430419
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Tidskriftsartikel (refereegranskat)abstract
- The 113I nucleus has been studied using the 58Ni(58Ni,3p) reaction at 250 MeV with the Gammasphere/ Microball facility. Gamma-ray three-and four-fold data gated by charged particle combinations were analyzed. Multipolarities of the γ rays were assigned following the angular correlation measurements. The present study is focused on the high spin properties, where the structure is dominated by 2p-2h excitations across the Z=50 gap. Ten decoupled bands showing the features of smooth band termination were observed; three of those bands are linked to known low-spin states, which allows the identification of configurations by direct comparisons with configuration-dependent cranked Nilsson-Strutinsky calculations. The yrast band, which was linked along with the signature partner, was followed up to (101/2+) and ℏω∼1.3 MeV. The other linked band was a negative-parity band observed up to (95/2-). Tentative configurations for the unlinked bands are discussed. Comparisons with the theoretical results suggest that the band built on a configuration involving the neutron i13/2 intruder orbital originating from the N=6 harmonic oscillator subshell was observed in this experiment.
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| 39. |
- Sylvan, G N, et al.
(författare)
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Deformation driving intruder orbitals in Kr-77
- 1997
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Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 56:2, s. 772-781
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Tidskriftsartikel (refereegranskat)abstract
- High-spin states in Kr-77 were identified via analysis of prompt gamma-gamma coincidences in the Ni-58(Si-29,2 alpha 2p) reaction at 128 MeV at the Gammasphere facility. Evaporation channel selection was achieved using the 95 element Microball charged-particle detector. 27 new states and 42 new transitions were found, The positive-parity bands were confirmed and the alpha=-1/2 band extended to 39/2(+). The negative-parity signature pair was extended to 31/2(-) and 37/2(-). Two new high-lying negative-parity bands were found extending from a state of spin I = 15/2 and energy 2.6 MeV to 17.4 MeV at I = (55/2). The new bands appear highly deformed and become yrast at high spin. A three-quasiparticle structure based on deformation driving, low-K unique-parity and intruder orbitals is suggested for them.
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| 40. |
- Yu, C. H., et al.
(författare)
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Comparison of Superdeformed Bands in 61Zn and 60Zn: Possible Evidence for T=0 Pairing
- 1999
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 60:3
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Tidskriftsartikel (refereegranskat)abstract
- The yrast superdeformed band in Zn-61 has been established using Si-28(Ar-36, 2pn)Zn-61 and Ca-40(Si-29, 2 alpha)Zn-61 fusion-evaporation reactions. The excitation energy of this band was determined via two transitions that link this band to the normally deformed states. Lifetime analysis of this band resulted in a quadrupole moment of Q(t) = 3.0 +/- (0.5)(0.4)e b, which corresponds to a deformation of beta(2) = 0.50+/-(0.07)(0.06). A comparison of the J((2)) dynamical moments of inertia of the yrast superdeformed band in Zn-61 with those in Zn-60 shows a nearly complete blocking of the observed alignment in Zn-60, indicating that T=0 proton-neutron pair correlations may be present in Zn-60. [S0556-2813(99)51109-6].
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| 41. |
- Yu, C. H., et al.
(författare)
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Superdeformed and Highly Deformed Bands in 65Zn and Neutron-proton Interactions in Zn Isotopes
- 2000
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 62:4
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Tidskriftsartikel (refereegranskat)abstract
- Superdeformed and highly deformed rotational bands were established in Zn-65 using the Ca-40(Si-29,4p)Zn-65 reaction, and averaged quadrupole moments were measured for two of these bands. The configurations of these bands were assigned based on Hartree-Fock calculations. One of the three bands exhibits at low (h) over bar omega a rise in the J((2)) dynamic moments of inertia that is similar to the alignment gain observed in Zn-60. A comparison of the rotational band configurations and their J((2)) moments of inertia for light Zn isotopes suggests that the rise in J((2)) is most likely caused by np interactions associated with the valence protons and neutrons occupying the g(9/2) intruder orbits.
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