| 1. |
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| 2. |
- Llewellyn, R. D. O., et al.
(författare)
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Establishing the Maximum Collectivity in Highly Deformed N = Z Nuclei
- 2020
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Ingår i: Physical Review Letters. - : American Physical Society. - 0031-9007 .- 1079-7114. ; 124:15
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Tidskriftsartikel (refereegranskat)abstract
- The lifetimes of the first excited 2(+) states in the N = Z nuclei Zr-80, Y-78, and Sr-76 have been measured using the gamma-ray line shape method following population via nucleon-knockout reactions from intermediate-energy rare-isotope beams. The extracted reduced electromagnetic transition strengths yield new information on where the collectivity is maximized and provide evidence for a significant, and as yet unexplained, odd-odd vs even-even staggering in the observed values. The experimental results are analyzed in the context of state-of-the-art nuclear density-functional model calculations.
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| 3. |
- Llewellyn, R. D. O., et al.
(författare)
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Spectroscopy of proton-rich Zr-79 : Mirror energy differences in the highly-deformed fpg shell
- 2020
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Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 811
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Tidskriftsartikel (refereegranskat)abstract
- Energy differences between isobaric analogue states have been extracted for the A = 79, Zr-79/Y-79 mirror pair following their population via nucleon-knockout reactions from intermediate-energy rare-isotope beams. These are the heaviest nuclei where such measurements have been made to date. The deduced mirror energy differences (MED) are compared with predictions from a new density-functional based approach, incorporating isospin-breaking effects of both Coulomb and nuclear charge-symmetry breaking and configuration mixing.
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| 4. |
- Assié, M., et al.
(författare)
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Neutron correlations in 6He viewed through nuclear break-up
- 2009
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Ingår i: European Physical Journal A. - : Springer Science and Business Media LLC. - 1434-6001 .- 1434-601X. ; 42:3, s. 441-446
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Tidskriftsartikel (refereegranskat)abstract
- The nuclear break-up of He-6 on a Pb-208 target was studied at 20 A MeV using a secondary beam of He-6 produced by the SPIRAL facility at GANIL. alpha-particles were detected in coincidence with two neutrons with a large angular coverage and the reaction mechanism was identified. From the distribution of the relative angles between the two neutrons the correlation function was extracted. It shows a strong correlation at small relative angles attributed to the contribution of the di-neutron configuration of He-6.
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| 5. |
- Charity, R. J., et al.
(författare)
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Two-proton decay of the 6Be ground state and the double isobaric analog of 11Li
- 2013
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Ingår i: Journal of Physics: Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 420:1
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Konferensbidrag (refereegranskat)abstract
- Two-proton decay is discussed in a number of light isobaric multiplets. For the lightest two-proton emitter, 6Be, the momentum correlations between the three decay products were measured and found to be consistent with quantum-mechanical three-cluster-model calculations. Two-proton decay was also found for two members of the A=8 and A=11 quintets. Finally, a third member of the A=11 sextet, the double isobaric analog of the halo nucleus 11Li in 11B was observed by its two-proton decay.
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| 6. |
- Petri, M., et al.
(författare)
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Structure of C-16: Testing shell model and ab initio approaches
- 2012
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Ingår i: Physical Review C - Nuclear Physics. - 2469-9985 .- 2469-9993. ; 86:4, s. Art. no. 044329-
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Tidskriftsartikel (refereegranskat)abstract
- Excited states in C-16 were populated via the Be-9(N-17,C-16+gamma)X one-proton knockout reaction. The lifetime of the 2(1)(+) state in C-16 was measured using the recoil distance method. The extracted lifetime of tau(+)(21) = 11.4(-0.9)(+0.8)(stat) +/- 0.7(syst(B rho))(-1.5)(+0.0)(syst(feeding)) ps yields a deduced B(E2;2(1)(+) -> 0(1)(+)) = 4.21(-0.26)(+0.34)(stat)(-0.24)(+0.28)(syst(B rho))(-0.00)(+0.64)(syst(feeding)) e(2)fm(4) value in good agreement with a previous measurement. The one-proton knockout cross section is used to extract the proton amplitude of the C-16 2(1)(+) state, which confirms the neutron dominant character of this state. Gamma-ray branching ratios between the 2(2)(+) state and the 2(1)(+) and ground states were also determined. The results are compared with p-sd shell model and no-core shell model (with NN and NN + NNN) calculations. The inclusion of three-body forces are essential in order for the no-core shell model calculations to reproduce the experimental findings on the gamma-ray branching ratios.
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| 7. |
- Assie, M., et al.
(författare)
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Neutron correlations in 6He viewed through nuclear break-up
- 2010
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Ingår i: Modern Physics Letters A. - 0217-7323 .- 1793-6632. ; 25:21-23, s. 1846-1849
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Tidskriftsartikel (refereegranskat)abstract
- Nuclear break-up as a tool to study neutron correlations is investigated both theoretically and experimentally. First a time dependent theory going beyond mean field has been developed and shows that correlations between nucleons can be probed through nuclear break-up. Secondly, nuclear break-up of He-6 on Pb-208 target was studied at 20 A.MeV using a secondary beam of He-6 produced by the SPIRAL facility at GANIL. From the correlation function, a strong contribution of the di-neutron configuration of He-6 is found.
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| 8. |
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| 9. |
- Chatterjee, A., et al.
(författare)
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1n and 2n transfer with the borromean nucleus He-6 near the Coulomb barrier
- 2008
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 101:3, s. 032701-
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Tidskriftsartikel (refereegranskat)abstract
- Angular distributions for In and 2n transfer are reported for the He-6 + Cu-65 system at E-lab = 22.6 MeV. For the first time, triple coincidences between a particles, neutrons, and characteristic gamma rays from the targetlike residues were used to separate the contributions arising from In and 2n transfer. The differential cross sections for these channels, elastic scattering, and fusion were analyzed using a coupled reaction channels approach. The large measured ratio of the 2n-to-1n cross section and the strong influence of 2n transfer on other channels indicate that the dineutron configuration of He-6 plays a dominant role in the reaction mechanism.
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| 10. |
- Lemasson, A., et al.
(författare)
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Pair and single neutron transfer with Borromean He-8
- 2011
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Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 697:5, s. 454-458
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Tidskriftsartikel (refereegranskat)abstract
- Direct observation of the survival of Au-199 residues after 2n transfer in the He-8 + Au-197 system and the absence of the corresponding Cu-67 in the He-8 + Cu-65 system at various energies are reported. The measurements of the surprisingly large cross sections for Au-199, coupled with the integral cross sections for the various Au residues, is used to obtain the first model-independent lower limits on the ratio of 2n to in transfer cross sections from He-8 to a heavy target. A comparison of the transfer cross sections for He-6.8 on these targets highlights the differences in the interactions of these Borromean nuclei. These measurements for the most neutron-rich nuclei on different targets highlight the need to probe the reaction mechanism with various targets and represent an experimental advance towards understanding specific features of pairing in the dynamics of dilute nuclear systems.
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