Exclusive measurement of breakup reactions with the one-neutron halo nucleus<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow /><mml:mrow><mml:mn>11</mml:mn></mml:mrow></mml:msup></mml:mrow><mml:mi mathvariant="normal">Be</mml:mi></mml:math>

Palit, R.; Adrich, P.; Aumann, T.; Boretzky, K.; Carlson, B. V.; Cortina, D.; Pramanik, U. Datta; Elze, Th. W.; Emling, H.; Geißel, H.; Hellström, M.; Jones, K. L.; Kratz, J. V.; Kulessa, R.; Leifels, Y.; Leistenschneider, A.; Münzenberg, G.; Nociforo, C.; Reiter, P.; Simon, H.; Sümmerer, K.; Waluś, W.

doi:10.1103/physrevc.68.034318

Cited by 171 publications

(141 citation statements)

References 64 publications

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“…Another striking feature in the oxygen isotopic chain is the doubly magic nature of 22 O and 24 O [6][7][8][9][10][11] in strong contrast to the lighter elements, where the drip line is marked by nuclei exhibiting a loosely bound halo structure. The neutron-rich oxygen isotopes also provide interesting insights, when viewed coming from their stable isotones.…”

Section: Introductionmentioning

confidence: 99%

Beyond the neutron drip line: The unbound oxygen isotopes25O and26O

Caesar¹,

Simonis²,

Adachi³

et al. 2013

Phys. Rev. C

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Section: Introductionmentioning

confidence: 99%

Beyond the neutron drip line: The unbound oxygen isotopes25O and26O

Caesar¹,

Simonis²,

Adachi³

et al. 2013

Phys. Rev. C

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“…4 and hence the underestimated binding energy of the 1/2 + state. The theoretical predictions are compared to indirect measurements of the photodissociation process extracted from the scattering experiments of 11 Be on lead [55][56][57] and carbon [54,55] targets. Our phenomenological adjusted calculations show good agreement with the RIKEN data [55][56][57].…”

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confidence: 99%

CanAb InitioTheory Explain the Phenomenon of Parity Inversion inBe11?

et al. 2016

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The weakly bound exotic 11 Be nucleus, famous for its ground-state parity inversion and distinct n+ 10 Be halo structure, is investigated from first principles using chiral two-and three-nucleon forces. An explicit treatment of continuum effects is found to be indispensable. We study the sensitivity of the 11 Be spectrum to the details of the three-nucleon force and demonstrate that only certain chiral interactions are capable of reproducing the parity inversion. With such interactions, the extremely large E1 transition between the bound states is reproduced. We compare our photodisintegration calculations to conflicting experimental data and predict a distinct dip around the 3/2 − 1 resonance energy. Finally, we predict low-lying 3/2 + and 9/2 + resonances that are not or not sufficiently measured in experiments.The theoretical understanding of exotic neutron-rich nuclei constitutes a tremendous challenge. These systems often cannot be explained by mean-field approaches and contradict the regular shell structure. The spectrum of 11 Be has some very peculiar features. The 1/2 + ground state (g.s.) is loosely bound by 502 keV with respect to the n+ 10 Be threshold and is separated by only 320 keV from its parity-inverted 1/2 − partner [1, 2], which would be the expected g.s. in the standard shell-model picture. Such parity inversion, already noticed by Talmi and Unna [3] in the early 1960s, is one of the best examples of the disappearance of the N = 8 magic number with an increasing neutron to proton ratio. The next (n+n+ 9 Be) breakup threshold appears at 7.31 MeV [4], such that the rich resonance structure at low energies is dominated by the n+ 10 Be dynamics. Peculiar also is the electricdipole transition strength between the two bound states, which has attracted much attention since its first measurement in 1971 [5] and was remeasured in 1983 [6] and 2014 [7]. It is the strongest known transition between low-lying states, attributed to the halo character of 11 Be.An accurate description of this complex spectrum is anticipated to be sensitive to the details of the nuclear force [8], such that a precise knowledge of the nucleon-nucleon (NN) interaction, desirably obtained from first principles, is crucial. Moreover, the inclusion of three-nucleon (3N) effects has been found to be indispensable for an accurate description of nuclear systems [9,10]. The chiral effective field theory constitutes one of the most promising candidates for deriving the nuclear interaction. Formulated by Weinberg [11][12][13], it is based on the fundamental symmetries of QCD and uses pions and nucleons as relevant degrees of freedom. Within this theory NN, 3N and higher many-body interactions arise in a natural hierarchy [11][12][13][14][15][16][17]. The details of these interactions depend on the specific choices made during the construction. In particular the way the interactions are constrained to experimental data can have a strong impact [18].In this work we tackle the question if ab initio calculations can provide an accurate des...

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“…In the 2 + channel of Sn, however, the low-lying states, not even counting surface vibrations, are still fairly well localized on average, even at the neutron drip line. The structure of excited states in exotic nuclei has been much studied recently, both in nuclei between Li and O [1,2,3,4] and in heavier Ca [5] and Sn [6] isotopes. Lowenergy strength is often enhanced, and theorists have tried to understand the mechanisms responsible.…”

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Excited-state density distributions in neutron-rich nuclei

Terasaki

Engel

2007

Phys. Rev. C

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We calculate densities of excited states in the quasiparticle random-phase approximation (QRPA) with Skyrme interactions and volume pairing. We focus on low-energy peaks/bumps in the strength functions of a range of Ca, Ni, and Sn isotopes for J π = 0 + , 1 − , and 2 + . We define an "emittedneutron number", which we then use to distinguish localized states from scattering-like states. The degree of delocalization either increases as the neutron-drip line is approached or stays high between the stability line and the drip line. In the 2 + channel of Sn, however, the low-lying states, not even counting surface vibrations, are still fairly well localized on average, even at the neutron drip line. The structure of excited states in exotic nuclei has been much studied recently, both in nuclei between Li and O [1,2,3,4] and in heavier Ca [5] and Sn [6] isotopes. Lowenergy strength is often enhanced, and theorists have tried to understand the mechanisms responsible. Besides strength functions, they have examined transition densities, which can be measured and provide information on excited-state structure. Our earlier paper [7] contains an investigation of strength functions and transition densities in a large range of medium-heavy spherical nuclei, from one drip line to the other.Transition densities tell us about where in the nucleus transitions occur; they reflect the spatial distribution of products of single-particle and single-hole wave functions and, as a consequence, are always localized, though they can be very extended near the neutron drip line. In nuclei near stability large transition strength implies collectivity, which in turn tends to cause localization (as we shall see in giant resonances). Near the drip line, however, the familiar connection between strength and collectivity is less systematic at low energies. Reference [7] shows many examples of behavior like that characterizing light halo nuclei and predicted for certain 0 + states in heavy nuclei in Ref. [8]: large strength coming from noncollective transitions to very spatially-extended singleparticle states. Those excited states are usually unbound, and may not even be quasibound, that is they may be completely delocalized scattering states [8].In this letter we suggest a measure of localization and then investigate the extent to which the strong low-lying excited states are localized, independent of their collectivity. To uncover changes in structure near the drip line, we track the degree of localization as N increases in J π = 0 + , 1 − , and 2 + channels. Localization, which we analyze by examining diagonal density distributions of the excited states, has not been systematically studied before and offers a new window into excitations in exotic neutron-rich nuclei.We can adopt ideas from simple one-particle quantum mechanics to distinguish localized states from extended ones. If the energy of a single particle in, e.g., a squarewell potential is negative (Chap. 3 of Ref.[9]) then the tail of its wave function decays exponentially, and if th...

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Exclusive measurement of breakup reactions with the one-neutron halo nucleus11Be

Cited by 171 publications

References 64 publications

Beyond the neutron drip line: The unbound oxygen isotopes25O and26O

Beyond the neutron drip line: The unbound oxygen isotopes25O and26O

CanAb InitioTheory Explain the Phenomenon of Parity Inversion inBe11?

Excited-state density distributions in neutron-rich nuclei

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