| 1. |
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| 2. |
- Humbert, F., et al.
(author)
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Longitudinal and Transverse-Momentum Distributions of Li-9 Fragments from Break-up of Li-11
- 1995
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In: Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics. - 0370-2693. ; 347:3-4, s. 198-204
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Journal article (peer-reviewed)abstract
- Transverse and longitudinal momentum distributions of Li-9 fragments from Li-11 break-up reactions in C, Al and Pb targets have been measured at 280 MeV/u. The two-neutron removal cross-section was measured to be sigma(-2n), = 0.26 +/- 0.02 b for the carbon target, sigma(-2n) = 0.47 +/- 0.08 b for the aluminum target and sigma(-2n), = 1.9 +/- 0.4 b for the lead target. No significant difference is observed between the narrow widths (FWHM approximate to 47 MeV/c) of the transverse and longitudinal momentum distributions of the Li-9 fragments. The physical implications of this are discussed.
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| 3. |
- Nilsson, Thomas, 1965, et al.
(author)
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He-6 and neutron momentum distributions from He-8 in nuclear break-up reactions at 240 MeV/u
- 1996
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In: Nuclear Physics A. - 0375-9474. ; 598:3, s. 418-434
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Journal article (peer-reviewed)abstract
- Neutron and He-6 momentum distributions from He-8 break-up reactions in a C target have been measured at 240 MeV/u. The two-neutron removal cross section was found to be sigma(-2n) = 0.27 +/- 0.03 b. The nature of the momentum distributions is interpreted in some simple reaction scenarios.
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| 4. |
- Nilsson, Thomas, 1965, et al.
(author)
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Neutron Momentum Distributions from Core Break-up Reactions of Halo Nuclei
- 1995
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In: Europhysics Letters. - 0295-5075 .- 1286-4854. ; 30:1, s. 19-24
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Journal article (peer-reviewed)abstract
- Neutron angular distributions from violent break-up reactions of Li-11 and Be-11 have been measured at 28 MeV/u and 280 MeV/u and at 41 MeV/u and 460 MeV/u, respectively. The derived neutron momentum distributions show a narrow component in transverse momentum that is within uncertainties independent of beam energy and target charge. This component is suggested to be simply related to the momentum distribution of the loosely bound halo neutron(s) in the projectiles.
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| 5. |
- Zinser, M., et al.
(author)
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Invariant-mass spectroscopy of Li-10 and Li-11
- 1997
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In: Nuclear Physics A. - 0375-9474. ; 619:1-2, s. 151-176
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Journal article (peer-reviewed)abstract
- Break-up of secondary Li-11 ion beams (280 MeV/nucleon) on C and Pb targets into Li-9 and neutrons is studied experimentally. Cross sections and neutron multiplicity distributions are obtained, characterizing different reaction mechanisms. Invariant-mass spectroscopy for Li-11 and Li-10 is performed. The E1 strength distribution, deduced from electromagnetic excitation of Li-11 up to an excitation energy of 4 MeV comprises similar to 8% of the Thomas-Reiche-Kuhn energy-weighted sumrule strength. Two low-lying resonance-like structures are observed for Li-10 at decay energies of 0.21(5) and 0.62(10) MeV, the former one carrying 26(10)% of the strength and likely to be associated with an s-wave neutron decay. A strong di-neutron correlation in Li-11 can be discarded. Calculations in a quasi-particle RPA approach are compared with the experimental results for Li-10 and Li-11. (C) 1997 Elsevier Science B.V.
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| 6. |
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| 7. |
- Borge, M. J. G., et al.
(author)
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Elucidating halo structure by beta decay: beta gamma from the Li-11 decay
- 1997
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In: Physical Review C - Nuclear Physics. - 2469-9985 .- 2469-9993. ; 55:1, s. R8-R11
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Journal article (peer-reviewed)abstract
- New values for the gamma ray intensities following the beta decay of Li-11 are presented. Special emphasis is put on the determination of the Gamow-Teller transition Li-11 --> Be-11 (1/2(-), 320 keV) to the only bound excited state in Be-11. We show that a shell-model calculation can simultaneously reproduce the half-life of Li-11 and the newly measured branching ratio to the 1/2(-) state provided the Li-11 ground state wave function contains about 50% of s-wave neutron components.
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| 8. |
- Borge, M. J. G., et al.
(author)
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Probing the Li-11 halo structure through beta-decay into the Be-11(*) (18 MeV) state
- 1997
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In: Nuclear Physics A. - 0375-9474. ; 613:3, s. 199-208
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Journal article (peer-reviewed)abstract
- An experimental study of beta-delayed charged particles (H, He, Be) from Li-11 shows a beta-feeding to an excited state at 18.15(15) MeV in Be-11 with a large Gamow-Teller strength, B-GT greater than or equal to 1.6. Branching ratios and reduced widths of 2-, 3- and 5- particle decay channels of this state are extracted, A strong suppression of the neutron branch from the 18 MeV state to the Be-10(g.s.) is observed, We suggest that the measured partial width may be sensitive to the (p(1/2))(2) component in the Li-11 halo, A rough estimate indicates that the (p(1/2))(2) component is not the dominant one in the halo wave-function.
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| 9. |
- Mukha, I., et al.
(author)
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Observation of the Li-11(beta d) decay
- 1996
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In: Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 367:1-4, s. 65-69
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Journal article (peer-reviewed)abstract
- Experimental data from the decay of Li-11 show for the first time the presence of beta-delayed deuterons with a branching ratio larger than 10(-4). To distinguish between beta d and beta t events the decays of the daughter nuclei Li-9 and Li-8 were identified in the energy and decay time spectra. Furthermore, a time correlation analysis between the beta d events and the subsequent daughter decays was performed.
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| 10. |
- Mukha, I., et al.
(author)
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Super-strong beta-decay of Li-11 into Be-11* (18 MeV) state: A probe for halo p-wave component?
- 1997
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In: Nuclear Physics A. - 0375-9474. ; 616:1-2, s. C201-C207
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Conference paper (peer-reviewed)abstract
- An experimental study of beta-delayed charged particles (H, He, Be), neutrons and gamma-rays that follow the Li-11 beta-decay, clearly indicates a beta-feeding to an exited state at 18.1 MeV in Be-11 with a large Gamow-Teller strength, B-GT greater than or equal to 1.0. The large strength of this beta-transition implies a broad overlap of the Be-11* state at 18.1 MeV and the ground state of Li-11. The deduced width of this resonance is similar or equal to 1 MeV. A strong suppression of the branch from 18.1 MeV state into the Be-10+n channel is observed. This branch, with the largest decay energy, has a partial width less than 1% of the total width. A centrifugal barrier consideration fails to explain this effect. A possible consequence of the observed effect for the Li-11 structure is that the admixture of (p(1/2))(2) configuration in Li-11 might be small.
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