Optical potentials of halo and weakly bound nuclei

Bonaccorso, A.; Cârstoiu, F.

doi:10.1016/s0375-9474(02)00755-8

Cited by 51 publications

(80 citation statements)

References 42 publications

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“…There is a consistent preference for potentials with very weak imaginary parts, with values of W around 5-7 MeV. We systematically find r V < r W and large diffuseness parameters a V ≃ 0.9 fm in agreement with theoretical expectations for loosely bound nuclei [19,20]. A grid search procedure on the real depth of the potential allowed us to identify discrete ambiguities.…”

Section: A Woods-saxon Form Factorssupporting

confidence: 81%

Refractive versus resonant diffraction scattering of loosely bound6Li nuclei

Cârstoiu

Trache

2012

Phys. Rev. C

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We present a complete analysis of elastic scattering 6 Li+ 16 O at 4 and 5 MeV/nucleon. Using either traditional Woods-Saxon or a range of semi-microscopic folding form-factors we find that the data require deep, highly transparent potentials. Physically relevant solutions are selected according to dispersion relation. The intermediate angle structures and the oscillatory increase of the cross section at large angles is interpreted either as a pre-rainbow oscillation resulting from the interference of the barrier and internal barrier far-side scattering subamplitudes, or, equally well, as a resonant diffraction arising from two Regge poles located in peripheral waves. Both semi-classical and Regge pole approaches allow a dynamical separation of the resonant component of the S-matrix.

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Section: A Woods-saxon Form Factorssupporting

confidence: 81%

Refractive versus resonant diffraction scattering of loosely bound6Li nuclei

Cârstoiu

Trache

2012

Phys. Rev. C

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“…The 11 Be elastic scattering angular distribution has been reproduced within the OM, using as bare potential the one that reproduces 10 Be scattering, and adding a phenomenological surface Dynamic-Polarization-Potential (DPP). A good fit was obtained with a DPP having a large diffuseness of the order of 3.5 fm in agreement with [16]. The 11 Be data were also reproduced within the CDCC frame, showing that the suppression of the Coulomb nuclear interference peak is due to the combined effect of Coulomb and nuclear couplings to continuum.…”

Section: Elastic Scatteringsupporting

confidence: 71%

Reaction studies with low-energy weakly-bound beams at INFN-LNS

Pietro

Fernández‐García

Figuera

et al. 2016

EPJ Web of Conferences

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The reaction dynamics of collisions involving halo or weakly bound nuclei, at energies around the Coulomb barrier, can be strongly affected by the structure of such nuclei. Very strong entrance channel effects have been observed on various reaction pocess such as, elastic scattering, fusion and direct reactions when comparing collision induced by the 6 He and 11 Be halo nuclei with the ones induced by their cores 4 He and 10 Be. Collisions induced by the stable weakly bound nuclei 6 Li, 7 Li show also some peculiarities in comparison to the ones induced by well bound nuclei; coupling with the break-up channel is in fact very important in reproducing low energy data. In this contribution an overview of our present understanding of the discussed topic will be given along with the discussion of some new preliminary results.

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“…Couplings can be represented in the OM by the addition of a complex dynamic polarization potential (DPP) to the OP (see, e.g., [25] and references therein). In [26] the DPP was a surface potential calculated analytically and applied to the 11 Be þ 12 C data at 49:3 AMeV. The real part of the DPP was not considered in the calculations since it produced a negligible effect on the elastic-scattering fit.…”

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confidence: 99%

“…This diffuseness depends on the projectile characteristics and not on the target; it is in fact related to the decay length of the neutron initial state wave function [26]. We used a procedure similar to [26] to deduce the OP in the case of 11 Be þ 64 Zn. In the present case, all terms of the OP were extracted phenomenologically from a fit of the elastic-scattering AD.…”

mentioning

confidence: 99%

Elastic Scattering and Reaction Mechanisms of the Halo NucleusBe11around the Coulomb Barrier

Pietro

Randisi²,

Scuderi³

et al. 2010

Phys. Rev. Lett.

171

109

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Collisions induced by 9;10;11 Be on a 64 Zn target at the same c.m. energy were studied. For the first time, strong effects of the 11 Be halo structure on elastic-scattering and reaction mechanisms at energies near the Coulomb barrier are evidenced experimentally. The elastic-scattering cross section of the 11 Be halo nucleus shows unusual behavior in the Coulomb-nuclear interference peak angular region. The extracted total-reaction cross section for the 11 Be collision is more than double the ones measured in the collisions induced by 9;10 Be. It is shown that such a strong enhancement of the total-reaction cross section with 11 Be is due to transfer and breakup processes. A hundred years after Rutherford's scattering experiment [1], heavy-ion-elastic-scattering angular distributions (AD) are usually plotted as a ratio of the Rutherford cross section (i.e., pure Coulomb scattering). Such representation usually shows a decrease of the elastic cross section with the angle due to absorption at small impact parameters by nonelastic processes, and an oscillatory behavior. The latter, using the language of optics, is described in terms of refraction by nonabsorbing lenses (Coulomb rainbow model) or diffraction by sharp-edged, nonrefracting apertures (Fraunhofer or Fresnel diffraction model). However, the refraction or diffraction descriptions are oversimplifications of the realistic process; rather, the nucleus behaves as a ''cloudy crystal ball.'' The elasticscattering AD may show a peak resulting from the interference between the Coulomb and nuclear amplitudes (Coulomb-nuclear interference peak) [2], which, in analogy with the Coulomb rainbow model, is sometimes called the rainbow peak. Since elastic scattering is a peripheral process, it does not give information on the interior region of nuclei. It probes the tail of the wave function, and hence one can learn about surface properties, such as size of nuclei and surface diffuseness. Therefore, elastic scattering is an ideal tool to study peculiar nuclear structures as, for example, the nuclear halo. Such structure originates when very weakly bound nucleon(s) can tunnel into the classically forbidden region, giving rise to a diffuse tail surrounding a well-bound core. The behavior of the system in nuclear reactions is mostly determined by the tail of the wave function [3]. The reaction mechanisms may also be affected by the weak binding: at energies around the Coulomb barrier, couplings between the entrance channel and the continuum [4][5][6][7][8], as well as to the various reaction channels [9][10][11][12], are expected to be very important. Direct reactions, such as breakup or transfer, may be favored owing to the low binding energy, the extended tail of halo nuclei, and the large Q values for selected transfer channels.Almost all elastic-scattering and reaction mechanism studies around the barrier with halo nuclei have been performed with the 2n halo nucleus 6 He. All authors agree that, due to the 6 He structure, one has an enhancement of the total-reaction (T...

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Optical potentials of halo and weakly bound nuclei

Cited by 51 publications

References 42 publications

Refractive versus resonant diffraction scattering of loosely bound6Li nuclei

Refractive versus resonant diffraction scattering of loosely bound6Li nuclei

Reaction studies with low-energy weakly-bound beams at INFN-LNS

Elastic Scattering and Reaction Mechanisms of the Halo NucleusBe11around the Coulomb Barrier

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