First Direct Mass Measurement of the Two-Neutron Halo Nucleus<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mmultiscripts><mml:mi>He</mml:mi><mml:mprescripts /><mml:none /><mml:mn>6</mml:mn></mml:mmultiscripts></mml:math>and Improved Mass for the Four-Neutron Halo<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mmultiscripts><mml:mi>He</mml:mi><mml:mprescripts /><mml:none /><mml:mn>8</mml:mn></mml:mmultiscripts></mml:math>

Brodeur, M.; Brunner, T.; Champagne, Claudia; Ettenauer, S.; Smith, M.; Lapierre, A.; Ringle, R.; Ryjkov, V. L.; Bacca, Sonia; Delheij, P. P. J.; Drake, G. W. F.; Lunney, D.; Schwenk, A.; Dilling, J.

doi:10.1103/physrevlett.108.052504

Cited by 99 publications

(76 citation statements)

References 33 publications

(38 reference statements)

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“…Note, however that the average distance between the two neutrons is not very small (∼ 2 fm), and it can be expected that the influence on the charge radius will diminish when adding additional neutrons. Indeed, it has been shown experimentally that the charge radius increases for 6 He, but decreases again in 8 He [24]. Gamow shell model calculations [27], that incorporate continuum structures explicitly, confirm that the amplitude of the di-neutron configuration is reduced when going from 6 He to 8 He.…”

Section: Resultsmentioning

confidence: 83%

Microscopic description of translationally invariant core+N+Noverlap functions

Sääf¹,

Forssén²

2014

Phys. Rev. C

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We derive expressions for core + N + N overlap integrals starting from microscopic wave functions obtained in the ab initio no-core shell model. These overlap integrals correspond to three-body channel form factors and can be used to investigate the clustering of many-body systems into a core plus two nucleons. We consider the case when the composite system and the core are described in Slater determinant, harmonic oscillator bases, and we show how to remove spurious center of mass components exactly in order to derive translationally-invariant overlap integrals. We study in particular the Borromean 6 He nucleus using realistic chiral nuclear interactions, and we demonstrate that the observed clusterization in this system is a Pauli focusing effect. The inclusion of three-body forces has a small effect on this structure. In addition, we discuss the issue of absolute normalization for spectroscopic factors, which we show is larger than one. As part of this study we also perform extrapolations of ground-state observables and investigate the dependence of these results on the resolution scale of the interaction.

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Section: Resultsmentioning

confidence: 83%

Microscopic description of translationally invariant core+N+Noverlap functions

Sääf¹,

Forssén²

2014

Phys. Rev. C

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“…Experimentally, the onset of halo structure along the He isotopic chain is indicated by a jump in the measured charge and matter radii, from 4 He to 6 He. The root mean square (RMS) point-proton distribution radius r p , which may be deduced [37] from the measured charge radius, increases by ∼ 32% from 4 He [r p = 1.462(6) fm] to 6 He [r p = 1.934(9) fm] [38][39][40]. This increase may be understood as a consequence of halo structure, arising from the recoil of the charged α core against the halo neutrons (as well as possible contributions from swelling of the α core [40]).…”

Section: Resultsmentioning

confidence: 99%

Natural orbital description of the halo nucleus 6He

et al. 2017

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Ab initio calculations of nuclei face the challenge of simultaneously describing strong short-range internucleon correlations and the long-range properties of weakly-bound halo nucleons. Natural orbitals, which diagonalize the one-body density matrix, provide a basis which is better matched to the physical structure of the many-body wave function. We demonstrate that the use of natural orbitals significantly improves convergence for ab initio no-core configuration interaction calculations of the neutron halo nucleus 6 He, relative to the traditional oscillator basis.

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“…For p-shell nuclei, in particular, tremendous theoretical progress has already been achieved using variational and Green's function Monte Carlo (VMC, GFMC) techniques [1] and the nocore shell model (NCSM) [2]. Comparisons to experimental measurements of electromagnetic transition rates [3], matter radii [4] and masses [5], and spectroscopic factors obtained from single-nucleon transfer reactions [6][7][8] and (e, e p) proton removal reactions [9] have all demonstrated effects that are not well described by the conventional shell model.…”

Section: Introductionmentioning

confidence: 99%

Systematic study ofp-shell nuclei via single-nucleon knockout reactions

et al. 2012

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A systematic investigation of the inclusive cross sections for single-nucleon knockout reactions from p-shell nuclei has been performed. A total of seven reactions were studied for projectiles with masses between A = 7 and 10, having a wide range of nucleon separation energies. Results were obtained for a range of incident beam energies and targets. These differences were found to have a minimal impact on the deduced cross sections. Experimental results were compared to theoretical predictions based on variational Monte Carlo (VMC) nuclear structure calculations, whose radial overlap functions and neutron and proton densities were included in the reaction description. These results are compared with the conventional model, developed for heavier nuclei, that uses shell-model and Hartree-Fock structure inputs. The VMC-based calculations agreed with the experimental data for several reactions where deeply bound nucleons are removed but does not describe some of the more weakly bound nucleon removal cases with comparable accuracy.

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First Direct Mass Measurement of the Two-Neutron Halo NucleusHe6and Improved Mass for the Four-Neutron HaloHe8

Cited by 99 publications

References 33 publications

Microscopic description of translationally invariant core+N+Noverlap functions

Microscopic description of translationally invariant core+N+Noverlap functions

Natural orbital description of the halo nucleus 6He

Systematic study ofp-shell nuclei via single-nucleon knockout reactions

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