| 1. |
- Chulkov, L. V., et al.
(author)
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Three-body correlations in electromagnetic dissociation of Borromean nuclei: The He-6 case
- 2005
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In: Nuclear Physics A. - : Elsevier BV. - 0375-9474. ; 759:1-2, s. 23-42
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Journal article (peer-reviewed)abstract
- Dissociation of He-6 on a lead target has been studied at 240 MeV/u. The four-momenta of the two neutrons in coincidence with alpha-particles have been measured and used to reconstruct the three-body energy and angular correlations in the final state. For the first time, three-body correlations were included in the analysis of the He-6 dissociation data, and compared with calculations assuming a dipole mode for the electromagnetic dissociation. In addition, the experimental data have been analyzed using a series expansion of the final transition amplitude into hyperspherical functions, showing the importance of both nn and alpha n final-state interactions. It is shown that the dissociation process is governed by a transition of one neutron from the p-shell in the 6He ground state to the s-shell in the continuum further indicating that the role of the transition through an intermediate He-5(3/2(-)) state is more important than expected. (c) 2005 Elsevier B.V. All rights reserved.
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| 2. |
- Aksyutina, Yu, et al.
(author)
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Lithium isotopes beyond the drip line
- 2008
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In: Physics Letters B. - : Elsevier BV. - 0370-2693. ; 666:5, s. 430-434
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Journal article (peer-reviewed)abstract
- The unbound isotopes 10Li, 12Li and 13Li have been observed after nucleon-knockout reactions at relativistic energies with 11Li and 14Be beams impinging on a liquid hydrogen target. The channels , and were analysed in the ALADIN-LAND setup at GSI. The 10Li data confirm earlier findings, while the 12Li and 13Li nuclei were observed for the first time. The relative-energy spectrum shows that the ground state of 12Li can be described as a virtual s-state with a scattering length of -13.7(1.6) fm. A broad energy spectrum was found for the channel. Based on the assumption that the relative-energy spectrum is dominated by a correlated background presumably stemming from initial correlations in the 14Be ground-state, evidence for a 13Li resonance at 1.47(31) MeV above the threshold with a width around 2 MeV has been found.
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| 3. |
- Simon, H., et al.
(author)
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Systematic investigation of the drip-line nuclei 11Li and 14Be and their unbound subsystems 10Li and 13Be
- 2007
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In: Nuclear Physics A. - : Elsevier BV. - 0375-9474. ; 791:3-4, s. 267-
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Journal article (peer-reviewed)abstract
- Fragmentation reactions in a carbon target with beams of 11Li and 14Be at relativistic energies have been studied in a kinematically complete experiment at the ALADIN-LAND setup at GSI. Excited states in 11Li and 14Be were obtained from the data in the inelastic channel. The measured cross sections with the core nucleus in the final state show that in the 14Be case core polarization plays an important role. In the one-neutron knockout channels the measured angular correlations between fragment and neutron are asymmetric, which demonstrates the presence of states with different parities in the 11Li and 14Be ground states. For 10Li a low-lying virtual s-state, a p-state and evidence for a d-state could be extracted from the data, while the 12Be+n system shows resonances with more complicated structure.
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| 4. |
- Aksyutina, Yuliya, 1983, et al.
(author)
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Properties of the 7He ground state from 8He neutron knockout
- 2009
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In: Physics Letters B. - : Elsevier BV. - 0370-2693. ; 679:3, s. 191-196
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Journal article (peer-reviewed)abstract
- The unbound nucleus 7He, produced in neutron-knockout reactions with a 240 MeV/u 8He beam in a liquid-hydrogen target, has been studied in an experiment at the ALADIN-LAND setup at GSI. From an R-matrix analysis the resonance parameters for 7He as well as the spectroscopic factor for the 6He(0+) + n configuration in its ground-state have been obtained. The spectroscopic factor is 0.61 confirming that 7He is not a pure single-particle state. An analysis of 5He data from neutron-knockout reactions of 6He in a carbon target reveals the presence of an s-wave component at low energies in the α+n relative energy spectrum. A possible low-lying exited state in 7He observed in neutron knockout data from 8He in a carbon target and tentatively interpreted as a Iπ=1/2− state, could not be observed in the present experiment. Possible explanations of the shape difference between the 7He resonance obtained in the two knockout reactions are discussed in terms of target-dependence or different reaction mechanisms at relativistic energies.
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| 5. |
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| 6. |
- Danilin, B.V., et al.
(author)
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Three-body continuum energy correlations in Borromean halo nuclei. III. Short-range external fields
- 2007
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In: Physical Review C - Nuclear Physics. - 2469-9985 .- 2469-9993. ; 76, s. 064612-
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Journal article (peer-reviewed)abstract
- Energy correlations in transition from the bound state to the three-body continuum of Borromean halo nuclei are considered. A core+n+n three-body cluster model which reproduces the experimentally known properties of 6He and 11Li has been used to study the low-lying resonances and soft modes. An analysis of the correlated responses in 6He shows that in the case of the narrow 2+ resonance the transition energy correlations are the same as in the intrinsic correlated structure in 3->3 scattering. They differ significantly for wide second 2+ and first 1+ resonances, and also for the soft dipole and monopole modes, where due to the transition operators, the intertwinning of the ground state and the three-body continuum plays a significant role.
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| 7. |
- Grigorenko, L. V., et al.
(author)
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Complete correlation studies of two-proton decays: Be-6 and Fe-45
- 2009
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In: Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 677:1-2, s. 30-35
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Journal article (peer-reviewed)abstract
- The complete three-body correlation pictures are experimentally reconstructed for the two-proton decays of the Be-6 and (45)e ground states. We are able to see qualitative similarities and differences between these decays. They demonstrate very good agreement with the predictions of a theoretical three-body cluster model. Validity of the theoretical methods for treatment of the three-body Coulombic decays of this class is thus established by the broad range of lifetimes and nuclear masses spanned by these cases. Implementations for decay dynamics and nuclear structure of 2p emitters are discussed. (C) 2009 Elsevier B.V. All rights reserved.
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| 8. |
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| 9. |
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| 10. |
- Grigorenko, L. V., et al.
(author)
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Recent progress in the theory of two-proton radioactivity and three-body decay
- 2008
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In: Journal of Physics: Conference Series. - 1742-6588 .- 1742-6596. ; 111:1
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Journal article (peer-reviewed)abstract
- The current situation in the theory of three-body decay and experimental advances are briefly overviewed. The integral formula for decay widths of three-body states is introduced. Theoretical approach with a simplified Hamiltonian allows a semianalytical treatment of the process. The problem of the width of the first excited 3/2- state of 17Ne is resolved. The qualitative consequences of the model for simplified approaches are discussed. These include a better understanding of the diproton decay approximation and an introduction of a corrected "R-matrix" formula for three-body width. © 2008 IOP Publishing Ltd.
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