Microscopic description of the scissors mode and its fragmentation

Beuschel, T.; Draayer, J. P.; Rompf, D.; Hirsch, Jorge G.

doi:10.1103/physrevc.57.1233

Cited by 23 publications

(21 citation statements)

References 21 publications

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“…The pseudo-SU(3) shell model provides a further understanding of the M 1 transitions in nuclei such as the even-even 160−164 Dy and 156−160 Gd isotopes, specifically it reflects on the scissors and twist modes as well as the observed fragmentation (Fig. 7), that is, the break-up of the M 1 strength among several levels closely clustered around a few strong transition peaks in the 2-4 MeV energy region [148] (and references therein; for a detailed review on magnetic dipole excitations in nuclei, see Ref. [149]).…”

Section: Pseudo-spin Symmetry For Heavy Nucleimentioning

confidence: 99%

Symmetry-guided large-scale shell-model theory

Launey

Dytrych

Draayer

2016

Progress in Particle and Nuclear Physics

131

173

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In this review, we present a symmetry-guided strategy that utilizes exact as well as partial symmetries for enabling a deeper understanding of and advancing ab initio studies for determining the microscopic structure of atomic nuclei. These symmetries expose physically relevant degrees of freedom that, for large-scale calculations with QCD-inspired interactions, allow the model space size to be reduced through a very structured selection of the basis states to physically relevant subspaces. This can guide explorations of simple patterns in nuclei and how they emerge from first principles, as well as extensions of the theory beyond current limitations toward heavier nuclei and larger model spaces. This is illustrated for the ab initio symmetry-adapted no-core shell model (SA-NCSM) and two significant underlying symmetries, the symplectic Sp(3, R) group and its deformation-related SU(3) subgroup. We review the broad scope of nuclei, where these symmetries have been found to play a key role -from the light p-shell systems, such as 6 Li, 8 B, 8 Be, 12 C, and 16 O, and sd-shell nuclei exemplified by 20 Ne, based on first-principle explorations; through the Hoyle state in 12 C and enhanced collectivity in intermediate-mass nuclei, within a no-core shell-model perspective; up to strongly deformed species of the rare-earth and actinide regions, as investigated in earlier studies. A complementary picture, driven by symmetries dual to Sp(3, R), is also discussed. We briefly review symmetry-guided techniques that prove useful in various nuclear-theory models, such as Elliott model, ab initio SA-NCSM, symplectic model, pseudo-SU(3) and pseudo-symplectic models, ab initio hyperspherical harmonics method, ab initio lattice effective field theory, exact pairing -plusshell model approaches, and cluster models, including the resonating-group method. Important implications of these approaches that have deepened our understanding of emergent phenomena in nuclei, such as enhanced collectivity, giant resonances, pairing, halo, and clustering, are discussed, with a focus on emergent patterns in the framework of the ab initio SA-NCSM with no a priori assumptions.

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Section: Pseudo-spin Symmetry For Heavy Nucleimentioning

confidence: 99%

Symmetry-guided large-scale shell-model theory

Launey

Dytrych

Draayer

2016

Progress in Particle and Nuclear Physics

131

173

View full text Add to dashboard Cite

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“…These values are very similar to those used in the pseudo SU(3) description of even-even nuclei [20,14]. They are larger than those used in standard calculations of B(E2) strengths [16] due to the passive role assigned to the nucleons in unique parity orbitals, whose contribution to the quadrupole moments is parametrized in this way.…”

Section: The Pseudo Su(3) Hamiltonianmentioning

confidence: 53%

“…While pairing is fundamental to obtaining the correct moment of inertia of the rotational bands, it has a relatively small effect on the overall wave functions [13]. An analysis of the SU(3) content of wave functions obtained in large shell-model diagonalizations [21], as well as the excellent description of ground and excited bands in heavy deformed even- [14,22] and odd-mass [15] nuclei strongly support this statement.…”

Section: The Pseudo Su(3) Basismentioning

confidence: 70%

“…They are a small subset of all the possible irreps, and involve only 4 proton and 3 neutron irreps. In this strongly truncated space it is possible to describe the low energy spectra of even-even nuclei [14,22] and normal parity bands in odd-mass nuclei [15]. The validity of the pseudo SU(3) symmetry is the rationale behind this successful truncation scheme.…”

Section: The Pseudo Su(3) Basismentioning

confidence: 99%

“…As can be seen in [14,15], by using an schematic Hamiltonian parametrized according to systematics [16,17], it is possible to describe the low-lying energy spectrum of even-and odd-mass heavy deformed nuclei. While the application of the model to other deformed rare-earth and actinide nuclei is in order, in the present contribution we will address some specific questions about the pseudo SU(3) model.…”

Section: Introductionmentioning

confidence: 99%

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Pseudo SU(3) shell model: Normal parity bands in odd-mass nuclei

2000

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A pseudo shell SU(3) model description of normal parity bands in 159 Tb is presented. The Hamiltonian includes spherical Nilsson singleparticle energies, the quadrupole-quadrupole and pairing interactions, as well as three rotor terms. A systematic parametrization is introduced, accompanied by a detailed discussion of the effect each term in the Hamiltonian has on the energy spectrum. Yrast and excited band wavefunctions are analyzed together with their B(E2) values.

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Nuclear Data Sheets for

Reich

2005

Nuclear Data Sheets

117

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Microscopic description of the scissors mode and its fragmentation

Cited by 23 publications

References 21 publications

Symmetry-guided large-scale shell-model theory

Symmetry-guided large-scale shell-model theory

Pseudo SU(3) shell model: Normal parity bands in odd-mass nuclei

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