| 1. |
- 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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| 2. |
- 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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| 3. |
- Kanungo, R., et al.
(author)
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One-Neutron Removal Measurement Reveals O-24 as a New Doubly Magic Nucleus
- 2009
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In: Physical Review Letters. - 1079-7114 .- 0031-9007. ; 102:15
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Journal article (peer-reviewed)abstract
- The first measurement of the momentum distribution for one-neutron removal from O-24 at 920A MeV performed at GSI, Darmstadt is reported. The observed distribution has a width (FWHM) of 99 +/- 4 MeV/c in the projectile rest frame and a one-neutron removal cross section of 63 +/- 7 mb. The results are well explained with a nearly pure 2s(1/2) neutron spectroscopic factor of 1.74 +/- 0.19 within the eikonal model. This large s-wave probability shows a spherical shell closure thereby confirming earlier suggestions that O-24 is a new doubly magic nucleus.
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| 4. |
- Maierbeck, P., et al.
(author)
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Probing the single particle structure around Ca-54 with one-neutron knock-out
- 2008
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In: AIP Conference Proceedings. - 1551-7616 .- 0094-243X. ; 1012, s. 89-93
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Conference paper (peer-reviewed)abstract
- The nuclei Ca-47 and Ti-55 were populated in one-neutron knock-out reactions at relativistic energies. Momentum distributions of the residual nuclei as well as gamma-ray spectra were measured at the GSI fragment separator (FRS). Preliminary results of the ongoing analysis including cross sections and spin/parity assignments are presented.
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| 5. |
- Maierbeck, P., et al.
(author)
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Structure of 55Ti from relativistic one-neutron knockout
- 2009
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In: Physics Letters B. - : Elsevier BV. - 0370-2693. ; 675:1, s. 22-27
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Journal article (peer-reviewed)abstract
- Results are presented from a one-neutron knockout reaction at relativistic energies on 56Ti using the GSI FRS as a two-stage magnetic spectrometer and the Miniball array for gamma-ray detection. Inclusive and exclusive longitudinal momentum distributions and cross-sections were measured enabling the determination of the orbital angular momentum of the populated states. First-time observation of the 955(6) keV -hole state in 55Ti is reported. The measured data for the first time proves that the ground state of 55Ti is a 1/2- state, in agreement with shell-model calculations using the GXPF1A interaction that predict a sizable N=34 gap in 54Ca.
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| 6. |
- Nociforo, C., et al.
(author)
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Shell Closure N=16 in O-24
- 2009
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In: AIP Conference Proceedings. - 1551-7616 .- 0094-243X. ; 1165, s. 90-93 461
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Conference paper (peer-reviewed)abstract
- Advanced nuclear structure models predict the presence of the shell closures N=14, 16 in neutron-rich O isotopes rather than N=20. Spectroscopic investigations performed at the neutron drip line have recently confirmed such predictions showing that the O-24 is a doubly magic nucleus (Z=8, N=16). Predictions within the shell model calculation for the O-23,O-24 ground state have been confirmed measuring their spectroscopic factors. Results obtained in one-neutron removal reactions performed by using in-flight radioactive ion beams produced at the Fragment Separator FRS of GSI are reported.
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