Quadrupole and octupole collectivity in 148Nd

Ibbotson, R. W.; White, C.A.; Czosnyka, T.; Butler, P. A.; Clarkson, N.; Cline, D.; Cunningham, R.A.; Devlin, M.; Helmer, Karl G.; Hoare, T.H.; Hughes, James; Jones, G. D.; Kavka, A.E.; Kotliński, B.; Poynter, R. J.; Regan, P. H.; Vogt, E.G.; Wadsworth, R.; Watson, D. L.; Wu, C. Y.

doi:10.1016/s0375-9474(97)00145-0

Cited by 36 publications

(27 citation statements)

References 34 publications

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“…Quoted errors on the various fit values reflect both the uncertainties associated with the data and those originating from correlations between the various fit parameters-see Refs. [14,18] for details. Note that the resulting E1 matrix elements are constrained primarily by the available data [9] on branching ratios in the decays from the states of interest and display little sensitivity to the Coulomb excitation yields.…”

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confidence: 99%

Direct Evidence of Octupole Deformation in Neutron-RichBa144

Bucher¹,

Zhu²,

Wu³

et al. 2016

Phys. Rev. Lett.

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149

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The neutron-rich nucleus 144 Ba (t 1/2 =11.5 s) is expected to exhibit some of the strongest octupole correlations among nuclei with mass numbers A less than 200. Until now, indirect evidence for such strong correlations has been inferred from observations such as enhanced E1 transitions and interleaving positive-and negative-parity levels in the ground-state band. In this experiment, the octupole strength was measured directly by sub-barrier, multi-step Coulomb excitation of a postaccelerated 650-MeV 144 Ba beam on a 1.0-mg/cm 2 208 Pb target. The measured value of the matrix element, 3 − 1 M(E3) 0 + 1 = 0.65( +17 −23 ) eb 3/2 , corresponds to a reduced B(E3) transition probability of 48( +25 −34 ) W.u. This result represents an unambiguous determination of the octupole collectivity, is larger than any available theoretical prediction, and is consistent with octupole deformation.

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confidence: 99%

Direct Evidence of Octupole Deformation in Neutron-RichBa144

Bucher¹,

Zhu²,

Wu³

et al. 2016

Phys. Rev. Lett.

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149

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“…Such an enhancement was experimentally observed in 144 Ba [30]. In Figs.5 and 6 the calculated transition strengths (matrix elements or transition probabilities) for the E1 transitions connecting the states of the GSB and K π = 0 − band are compared with experiment [1], [31] ( 226 Ra), [32] ( 148 Nd) and the predictions of some other collective models incorporating octupole or/and dipole degrees of freedom.…”

Section: Transition Probabilitiesmentioning

confidence: 74%

Simultaneous description of low-lying positive and negative parity bands in heavy even-even nuclei

Ganev

2014

Phys. Rev. C

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The low-lying spectra including the first few excited positive and negative parity bands of some heavy even-even nuclei from the rare earth and actinide mass regions are investigated within the framework of the symplectic Interacting Vector Boson Model with Sp(12,R) dynamical symmetry group. Symplectic dynamical symmetries allow the change of the number of excitation quanta or phonons building the collective states providing for larger representation spaces and richer subalgebraic structures to incorporate more complex nuclear spectra. The theoretical predictions for the energy levels and the electromagnetic transitions between the collective states of the ground state band and K π = 0 − band are compared with experiment and some other collective models incorporating octupole and/or dipole degrees of freedom. The energy staggering which is a sensitive indicator of the octupole correlations in the even-even nuclei is also calculated and compared with experiment. The results obtained for the energy levels, energy staggering and transition strengths reveal the relevance of the used dynamical symmetry of the model for the simultaneous description of both positive and negative parity low-lying collective bands.

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“…In the case of a vibrator, the coupling of an octupole phonon to the ground state rotational band will give zero values for matrix elements such as 1 − ||E3||4 + , because an aligned octupole phonon would couple the 4 + state to a 7 − state. Although the radioactive beam experiments do not have sensitivity to this quantity, this effect has been observed for 148 Nd in the Z ≈ 56, N ≈ 88 octupole region [33], while for 226 Ra the intrinsic moment derived from the measured 1 − ||E3||4 + is similar to that derived from the value of 0 + ||E3||3 − [25].…”

Section: Discussionmentioning

confidence: 89%

Pear-shaped Nuclei: Nuclear Models and the Standard Model

Butler¹

2014

Acta Phys. Pol. B

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For certain combinations of protons and neutrons, there is a theoretical expectation that the shape of nuclei can assume octupole deformation, which would give rise to reflection asymmetry or a "pear shape" in the intrinsic frame, either dynamically (octupole vibrations) or statically (permanent octupole deformation). In this paper, I will briefly review the historic evidence for reflection asymmetry in nuclei, describe how recent experiments carried out at REX-ISOLDE are constraining nuclear theory and how they contribute to tests of extensions of the Standard Model, and look at future prospects for this field.

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Quadrupole and octupole collectivity in 148Nd

Cited by 36 publications

References 34 publications

Direct Evidence of Octupole Deformation in Neutron-RichBa144

Direct Evidence of Octupole Deformation in Neutron-RichBa144

Simultaneous description of low-lying positive and negative parity bands in heavy even-even nuclei

Pear-shaped Nuclei: Nuclear Models and the Standard Model

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