On the mechanism of backbending and signature inversion

Hara, Kenji; Sun, Yang

doi:10.1007/bf01282929

Cited by 11 publications

(3 citation statements)

References 23 publications

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“…The triaxial projected shell model (TPSM) carries out the configuration mixing based on a Nilsson mean field with the angular momentum projection technique [30]. It has been successfully applied to study the nuclear rotational excitations, including the backbending phenomena [31], the superdeformed rotational bands [32], the signature inversion [33], the γ bands [34], and the chiral [35][36][37] and wobbling [38] rotations, etc.…”

Section: Introductionmentioning

confidence: 99%

Nuclear matrix elements of neutrinoless double-$β$ decay in the triaxial projected shell model

Wang,

Zhao,

Meng

2021

Preprint

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The nuclear matrix elements of neutrinoless double-β decay for nuclei 76 Ge, 82 Se, 100 Mo, 130 Te, and 150 Nd are studied within the triaxial projected shell model, which incorporates simultaneously the triaxial deformation and quasiparticle configuration mixing. The low-lying spectra and the B(E2 : 0 + → 2 + ) values are reproduced well. The effects of the quasiparticles configuration mixing, the triaxial deformation, and the closure approximation on the nuclear matrix elements are studied in detail. For nuclei 76 Ge, 82 Se, 100 Mo, 130 Te, and 150 Nd, the nuclear matrix elements are respectively reduced by the quasiparticle configuration mixing by 6%, 7%, 2%, 3%, and 4%, and enhanced by the odd-odd intermediate states by 7%, 4%, 11%, 20%, and 14%. Varying the triaxial deformation γ from 0 • to 60 • for the mother and daughter nuclei, the nuclear matrix elements change by 41%, 17%, 68%, 14%, and 511% respectively for 76 Ge, 82 Se, 100 Mo, 130 Te, and 150 Nd, which indicates the importance of treating the triaxial deformation consistently in calculating the nuclear matrix elements.

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Section: Introductionmentioning

confidence: 99%

Nuclear matrix elements of neutrinoless double-$β$ decay in the triaxial projected shell model

Wang,

Zhao,

Meng

2021

Preprint

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“…Hamamoto, 10) using the particle-plus-rotor model, suggested that the γ deformation may not be so important. The work of Jain et al 11) within the framework of a model incorporating an axially symmetric rotor plus two particles suggests the mechanism of Coriolis mixing between a large number of bands, and Hara et al 12) proposed the crossing of decoupled bands to describe it. In addition, other studies have analyzed the effect introduced by including a proton-neutron interaction between the odd nucleons, for example, the works of Matsuzaki 13) and Tajima,14) and the effect introduced by considering different dynamical symmetries in the interacting boson model, for example, the work of Yoshida et al 15) Very recently, signature inversion in the A-80 region was investigated in detail by Zheng et al on the basis of a model incorporating an axially symmetric rotor plus two quasiparticles.…”

Section: §1 Introductionmentioning

confidence: 99%

On the Mechanism of Signature Inversion in the Doubly Odd Nuclei 80, 82Rb

Shen

et al. 2004

Progress of Theoretical Physics

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Several mechanisms have been proposed for signature inversion in the structure of A ∼ 80 odd-odd nuclei, but the corresponding theoretical calculations have not been conclusive. In the present work, the angular momentum projected shell model (PSM) is applied to the study of the nuclei 80,82 Rb. The results of the calculations regarding the positive parity yrast band for the configuration πg 9/2 ⊗ νg 9/2 and the negative parity yrast band for the configuration π(p 1/2 or p 3/2 or f 5/2 )⊗νg 9/2 are compared with experimental data. According to the interpretation provided by the projected shell model, the signature inversion displayed in the positive parity yrast band for these nuclei is a signal of a substantial quadrupole shape change that takes place with increasing spin: The nucleus evolves from a prolate shape at low spin through a triaxial shape to an oblate shape at high spin. In addition, we specify the nuclear shapes of these two bands in these two nuclei.

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“…The PSM carries out the shell model configuration mixing based on Nilsson mean field with the angular momentum projection technique [42]. It has been successfully used to investigate the backbending phenomena [43], superdeformed rotational bands [44], signature inversion [45], and γ bands [46,47], etc. Recently, this idea has also been implemented based on the self-consistent relativistic [48] and nonrelativistic [49] density functional theories.…”

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confidence: 99%

Multichiral facets in symmetry restored states: Five chiral doublet candidates in the even-even nucleus Nd136

et al. 2019

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A triaxial projected shell model including configurations with more than four quasiparticles in the configuration space is developed, and applied to investigate the recently reported five chiral doublets candidates in a single even-even nucleus 136 Nd. The energy spectra and transition probability ratios B(M 1)/B(E2) are reproduced satisfactorily. The configuration mixing along the rotational bands is studied by analyzing the intrinsic composition of the eigenfunctions. The chiral geometry of these nearly degenerate bands is examined by the K plot and the azimuthal plot, and the evolution from the chiral vibration to the static chirality with spin is clearly demonstrated for four pairs of partner bands. From the features in the azimuthal plot, it is difficult to interpret the other candidate as chiral partners. * mengj@pku.edu.cn Chirality is one of the hot topics in biology, chemistry, and physics. The chirality in atomic nuclei was first predicted theoretically by Frauendorf and Meng in 1997 [1]. The predicted topology, the mutually perpendicular angular momenta of the valence protons, valence neutrons, and the core, leads to the so-called spontaneous chiral symmetry breaking in the intrinsic frame. The restoration of the chiral symmetry in the laboratory frame can be manifested by the observation of a pair of nearly degenerate ∆I = 1 bands with the same parity. Within the framework of the adiabatic and configuration fixed constrained triaxial covariant density functional theory (CDFT) [2], a new phenomenon, the existence of multiple chiral doublets (abbreviated as MχD), i.e., more than one pair of chiral doublet bands in one single nucleus has been predicted [3-6]. Many experimental and theoretical efforts have been devoted to study chiral doublets in various mass regions. So far, around 60 pairs of chiral doublets candidates have been established in A ∼ 80 [7, 8], 100 [9-13], 130 [14-20], and 190 [21, 22] mass regions. The observation of chiral bands in different mass regions indicates that nuclear chirality could be universal. The experimental evidences for the MχD were reported in 133 Ce [23], 103 Rh [24], and 78 Br [8] which demonstrate the multiple facets of nuclear chirality. For the detailed experimental status, see the data compilation [25].Theoretically, the chiral doublet bands have been investigated by various approaches, for example, the particle rotor model (PRM) [1,[26][27][28][29], the tilted axis cranking model (TAC) [1,[30][31][32], the TAC approach with the random phase approximation [33] and the collective Hamiltonian [34,35], the interacting boson-fermion-fermion model [16,36,37], the generalized coherent state model [38] and the projected shell model (PSM) [39][40][41]. The PSM carries out the shell model configuration mixing based on Nilsson mean field with the angular momentum projection technique [42]. It has been successfully used to investigate the backbending phenomena [43], superdeformed rotational bands [44], signature inversion [45], and γ bands [46, 47], etc. Recently, this idea ...

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On the mechanism of backbending and signature inversion

Cited by 11 publications

References 23 publications

Nuclear matrix elements of neutrinoless double-$β$ decay in the triaxial projected shell model

Nuclear matrix elements of neutrinoless double-$β$ decay in the triaxial projected shell model

On the Mechanism of Signature Inversion in the Doubly Odd Nuclei 80, 82Rb

Multichiral facets in symmetry restored states: Five chiral doublet candidates in the even-even nucleus Nd136

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