Geometry of Borromean Halo Nuclei

Abstract

We discuss the geometry of the highly quantal nuclear three-body systems composed of a core plus two loosely bound particles. These Borromean nuclei have no single bound two-body subsystem. Correlation plays a prominent role. From consideration of the $B(E1)$ value extracted from electromagnetic dissociation, in conjunction with HBT-type analysis of the two valence-halo particles correlation, we show that an estimate of the over-all geometry can be deduced. In particular we find that the opening angle between the two neutrons in ${}^6$He and ${}^{11}$Li are, respectively, ${\theta }_{nn}={83^{\circ }}_{-10}^{+20}$ and ${66^{\circ }}_{-18}^{+22}$. These angles are reduced by about 12% to ${\theta }_{nn}={78^{\circ }}_{-18}^{+13}$ and ${58^{\circ }}_{-14}^{+10}$ if the laser spectroscopy values of the rms charge radii are used to obtain the rms distance between the cores and the center of mass of the two neutrons. The opening angle in the case of ${}^{11}$Li is more than 20% larger than recently reported by Nakamura \cite{Nak06}. The analysis is extended to ${}^{14}$Be and the two-proton Borromean nucleus ${}^{17}$Ne where complete data is still not available. Using available experimental data and recent theoretical calculations we find, ${\theta }_{nn}={64^0}_{-10}^{+9}$ and ${\theta }_{pp}=110^0$, respectively.

arXiv comment5 pages, one figure, version to appear in PRC, Rapid Communications

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• Nuclear Charge Radius of Li-9, Li-11: Halo Neutron: the influence of Halo Neutrons
• Laser Spectroscopic Determination of the 6He Nuclear Charge Radius
• Pairing correlations in nuclei on the neutron-drip line
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• Nuclear Radii of Unstable Nuclei
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• Two-neutron halo nuclei in one dimension: dineutron correlation and breakup reaction
• Searching for universality of dineutron correlation at the surface of Borromean nuclei
• Cooper pair sizes in 11Li and in superfluid nuclei: a puzzle?
• Are there good probes for the di-neutron correlation in light neutron-rich nuclei?
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• Two-proton correlation function for the pp -> pp+eta and pp -> pp+pions reactions
• Charge and Matter Form Factors of Two-Neutron Halo Nuclei in Halo Effective Field Theory at Next-to-leading-order
• Universal geometry of two-neutron halos and Borromean Efimov states close to dissociation
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• Percolation and Dissolution of Borromean Networks
• Semi-classical approaches to heavy-ion reactions: fusion, rainbow, and glory
• Di-neutron correlation in light neutron-rich nuclei
• Beyond the neutron-drip line: two-neutron decay of unbound nuclei
• Pairing Correlations in halo Nuclei