Identification of all intrinsic excitations below 2 MeV in<sup>168</sup>Er

Davidson, W.F.; Warner, D.D.; Casten, R. F.; Schreckenbach, K.; Börner, Hans G.; Simic, Julia; Stojanović, Milovan; Bogdanović, M.; Koički, S.; Gelletly, W.; Orr, G. B.; Stelts, M.L.

doi:10.1088/0305-4616/7/4/011

Cited by 133 publications

(53 citation statements)

References 31 publications

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“…As is well known from data [48,49], the ground states of deformed even-even nuclei consistently have quantum numbers I = 0 = K and positive parity. Low-lying vibrational states have K = 0 and |K| = 2 and positive parity.…”

Section: Spectramentioning

confidence: 67%

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Effective field theory for finite systems with spontaneously broken symmetry

Papenbrock

Weidenmüller

2014

Phys. Rev. C

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We extend effective field theory to the case of spontaneous symmetry breaking in genuinely finite quantum systems such as small superfluid systems, molecules or atomic nuclei, and focus on deformed nuclei. In finite superfluids, symmetry arguments alone relate the spectra of systems with different particle numbers. For systems with non-spherical intrinsic ground states such as atomic nuclei or molecules, symmetry arguments alone yield the universal features of the low-lying excitations as vibrations that are the heads of rotational bands. The low-lying excitations in deformed nuclei differ from those in molecules because of symmetry properties caused by pairing.

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Section: Spectramentioning

confidence: 67%

“…This essential element provides the only difference in the lowenergy spectra of molecules and of deformed nuclei. Indeed, there are no low-lying I π = 1 + states in deformed even-even nuclei [48,49].…”

Section: Spectramentioning

confidence: 99%

Effective field theory for finite systems with spontaneously broken symmetry

Papenbrock

Weidenmüller

2014

Phys. Rev. C

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“…2, where the B(E2) values for transitions within the γ-band of 168 Er are compared with experimental data from Ref. [2,8,14,16]. Table I and Fig.…”

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confidence: 99%

In-band and inter-band B(E2) values within the Triaxial Projected Shell Model

et al. 2002

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The Triaxial Projected Shell Model (TPSM) has been successful in providing a microscopic description of the energies of multi-phonon vibrational bands in deformed nuclei. We report here on an extension of the TPSM to allow, for the first time, calculations of B(E2) values connecting γ-and γγ-vibrational bands and the ground state band. The method is applied to 166,168 Er. It is shown that most of the existing B(E2) data can be reproduced rather well, thus strongly supporting the classification of these states as γ-vibrational states. However, significant differences between the data and the calculation are seen in those B(E2) values which involve odd-spin states of the γ-band. Understanding these discrepancies requires accurate experimental measurements and perhaps further improvements of the TPSM. PACS: 21.60. Cs, 21.10.Re, 21.10.Ky, 27.70.+q Recently two-phonon γγ-vibrational bands have been identified in a number of nuclei [1][2][3], where pronounced anharmonicities have been observed in the vibrational spectrum. A microscopic description of the energies and transition probabilities of two-phonon vibrational excitations remains a challenge to nuclear models. The Triaxial Projected Shell Model [4,5] is a new microscopic, fully quantum-mechanical model with a unified treatment of the vibrational and rotational states. In the TPSM approach, one introduces triaxiality in the deformed basis and performs exactly three-dimensional angular momentum projection [4]. In this way, the deformed vacuum state is much enriched by allowing all possible Kcomponents. Diagonalization mixes these components, and various excited bands emerge [5] besides the ground state (g.s.) band (K = 0). The excited K = 2 band describes the one-phonon γ-vibrational band; and the excited band with K = 4 accounts for the two-phonon γγ-band. The observed anharmonicities in the energies of multi-phonon vibrational bands occur quite naturally from the TPSM without including additional ingredients in the model [5]. The TPSM has recently been applied also to the study of transition quadrupole moments in the g.s. bands of γ-soft nuclei and the magnetic dipole properties of the γ-vibrational states [6,7]. However, inband and inter-band E2-transitions, which are important quantities in supporting classification of states, have not been studied yet.The purpose of this paper is to report a new extension of the TPSM which allows the calculation of B(E2) values for transitions connecting the g.s. band, the single γ, and double γγ vibrational bands. We have searched the entire rare-earth region for experimental inter-band B(E2) values that allow a comparison with our calculations. Data on absolute B(E2) values are sparse and only in few cases they are known for more than one or two members of the γ-band. In this paper we study B(E2) values for 166,168 Er, which are the best cases. These nuclei exhibit well established double-phonon excitations [2,3].168 Er is one of the most extensively studied nuclei in this mass region with several measured B(E2) value...

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“…The experimental data [27][28][29][33][34][35][36][37][38][39][40][41][42] and the results of calculations with the QPNM [6,15,22,43] are given in Table 1. The experimental energies and available data on the contribution of one-phonon components and their structure are presented in the table.…”

Section: Analysis Of Experimental Datamentioning

confidence: 99%

Confrontation between the quasiparticle-phonon nuclear model and the interacting boson model for deformed nuclei

Soloviev

1986

Z. Physik A - Atomic Nuclei

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The Ks=0 + , 2 + and 4 + states are considered in doubly even deformed nuclei. It is shown that in the quasiparticle-phonon nuclear model (QPNM) and in the interacting boson model (IBM) a vibrational state has one dominating component. The states with + 0Z, 0F, 2+a, 4[ and 4f have a dominating one-phonon component within the QPNM and a two-or three-boson component within the IBM. According to the QPNM the contribution of two-phonon components to the wave functions of these states is less than 10%, i.e. there is a qualitative discrepancy in describing the structure of these states within the QPNM and the IBM. The experimental data indicate the existence in these states of one-phonon or two-quasiparticle components. They are rather well described within the QPNM. These states cannot be described within the IBM. This is due to the fact that the IBM takes into account only a small part of the space of two-quasiparticle states, just the one entering into fi-and 7-vibrational states.

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Identification of all intrinsic excitations below 2 MeV in¹⁶⁸Er

Cited by 133 publications

References 31 publications

Effective field theory for finite systems with spontaneously broken symmetry

Effective field theory for finite systems with spontaneously broken symmetry

In-band and inter-band B(E2) values within the Triaxial Projected Shell Model

Confrontation between the quasiparticle-phonon nuclear model and the interacting boson model for deformed nuclei

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Identification of all intrinsic excitations below 2 MeV in168Er

Cited by 133 publications

References 31 publications

Effective field theory for finite systems with spontaneously broken symmetry

Effective field theory for finite systems with spontaneously broken symmetry

In-band and inter-band B(E2) values within the Triaxial Projected Shell Model

Confrontation between the quasiparticle-phonon nuclear model and the interacting boson model for deformed nuclei

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Identification of all intrinsic excitations below 2 MeV in¹⁶⁸Er