Comprehensive studies of low-spin collective excitations in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow /><mml:mrow><mml:mn>94</mml:mn></mml:mrow></mml:msup></mml:mrow><mml:mi mathvariant="normal">Mo</mml:mi></mml:math>

Fransen, C.; Pietralla, N.; Ammar, Z.; Bandyopadhyay, D.; Boukharouba, N.; Brentano, P. von; Dewald, Α.; Gableske, J.; Gade, A.; Jolie, J.; Kneißl, U.; Lesher, S. R.; Lisetskiy, A. F.; McEllistrem, M. T.; Merrick, M.; Pitz, H. H.; Warr, N.; Werner, V.; Yates, S. W.

doi:10.1103/physrevc.67.024307

Cited by 116 publications

(92 citation statements)

References 64 publications

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“…The existence of such a multiphonon structure with MS character was discovered in the nuclide 94 Mo [7,8] and can be explained by the F -spin symmetric O(6) limit of the IBM-2 [2]. Recent measurements on 94 Mo and other N = 52 isotones confirm [9][10][11][12][13][14][15] the initial findings as a general phenomenon [16]. Here, the evolution of MS states in N = 52 isotones can be tracked over different proton shells.…”

Section: Introductionmentioning

confidence: 58%

Relativistic Coulomb excitation of Kr88

Moschner¹,

Blazhev²,

Jolie³

et al. 2016

Phys. Rev. C

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Relativistic Coulomb excitation of 88KrMoschner, K.; Blazhev, A.; Jolie, J.; Warr, N.; Boutachkov, P.; Bednarczyk, P.; Sieja, K.; Algora, A.; Ameil, F.; Bentley, M. A.; Brambilla, S.; Braun, N.; Camera, F. To investigate the systematics of mixed-symmetry states in N = 52 isotones, a relativistic Coulomb excitation experiment was performed during the PreSPEC campaign at the GSI Helmholtzzentrum für Schwerionenforschung to determine E2 transition strengths to 2 + states of the radioactive nucleus 88 Kr. Absolute transition rates could be measured towards the first and third 2 + states. For the latter a mixed-symmetry character is suggested on the basis of the indication for a strong M1 transition to the fully symmetric 2 1 + state, extending the knowledge of the N = 52 isotones below Z = 40. A comparison with the proton-neutron interacting boson model and shell-model predictions is made and supports the assignment.

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Section: Introductionmentioning

confidence: 58%

Relativistic Coulomb excitation of Kr88

Moschner¹,

Blazhev²,

Jolie³

et al. 2016

Phys. Rev. C

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“…However, pronounced MSSs have recently also been observed in weakly collective nuclei especially in N = 52 isotones. Multiphonon structures of MSSs are observed in the nucleus 94 Mo [10,11,12], in neighboring nuclei * Electronic address: jholt@triumf.ca [13,14,15], and recently the first MSSs in an oddmass nearly-spherical nucleus were identified in 93 Nb [16]. Even though the experimental properties of MSSs in this region have been well described within the framework of the IBM-2 [17,18], the nuclear shell model (SM) [14,19], and the quasiparticle-phonon model [20], the question of how these states arise and evolve has not yet been answered.…”

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confidence: 99%

Microscopic restoration of proton-neutron mixed symmetry in weakly collective nuclei

et al. 2007

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Starting from the microscopic low-momentum nucleon-nucleon interaction V low k , we present the first systematic shell model study of magnetic moments and magnetic dipole transition strengths of the basic low-energy one-quadrupole phonon excitations in nearly-spherical nuclei. Studying in particular the even-even N = 52 isotones from 92 Zr to 100 Cd , we find the predicted evolution of the predominantly proton-neutron non-symmetric state reveals a restoration of collective proton-neutron mixed-symmetry structure near mid-shell. This provides the first explanation for the existence of pronounced collective mixed-symmetry structures in weakly-collective nuclei.PACS numbers: 21.60. Cs, Mesoscopic quantum systems such as Bose-Einstein condensates, superconductors, and quark-gluon systems are some of the most intensely studied in contemporary physics [1,2]. Their dynamical properties are determined by the interplay and mutual balance of collective and single-particle degrees of freedom. In two fluid systems such as atomic nuclei, the presence of an isospin degree of freedom only serves to enhance this complexity. Of particular interest for understanding the physics of these systems is the microscopic origin of those excitations possessing collective two-fluid character. Collective quadrupole isovector excitations in the valence shell, socalled mixed-symmetry states (MSSs) [3], are the beststudied examples of this class of excitations. A special type of MSS, the 1 + scissor mode, was predicted to exist [4] and discovered [5] in atomic nuclei. It is not surprising then, that analogous scissor-mode states have subsequently been found in other two-fluid quantum systems such as trapped Bose-Einstein condensed gases [6,7], metallic clusters [8], and elliptical quantum dots [9].Even though MSSs are a common feature of two-fluid quantum systems, atomic nuclei are still the primary laboratory in which our understanding of them can be shaped. In the interacting boson model of heavy nuclei (IBM-2) the definition of MSSs is formalized by the bosonic F -spin symmetry [3]. It arises predominantly from a collective coupling of proton and neutron sub-systems, and when the proton/neutron (pn) valence spaces are large enough, strong coupling can arise between them. Naturally then, the best examples of pnsymmetric and MSSs would be expected at mid shells. However, pronounced MSSs have recently also been observed in weakly collective nuclei especially in N = 52 isotones. Multiphonon structures of MSSs are observed in the nucleus 94 Mo [10,11,12], in neighboring nuclei * Electronic address: jholt@triumf.ca [13,14,15], and recently the first MSSs in an oddmass nearly-spherical nucleus were identified in 93 Nb [16]. Even though the experimental properties of MSSs in this region have been well described within the framework of the IBM-2 [17,18], the nuclear shell model (SM) [14,19], and the quasiparticle-phonon model [20], the question of how these states arise and evolve has not yet been answered.In this Letter, we provide the first micros...

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“…Due to the absence of 2qp-states at low energies the mixed-symmetric QRPA-phonon is in all three nuclei at energies >4 MeV (see Fig. 8.10) [Fra03]. Furthermore the authors of Ref.…”

Section: Hexadecapole Statesmentioning

confidence: 99%

“…If the QPM calculations are correct the (n, n γ)-experiments of Refs. [Fra03,Fra05,Elh08] missed the main fragments of the one-phonon octupole mixed-symmetry states.…”

Section: Hexadecapole Statesmentioning

confidence: 99%

The Two-Photon Decay of the 11-/2 Isomer of 137Ba and Mixed-Symmetry States of 92,94Zr and 94Mo

Walz¹

2016

Springer Theses

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The first part of this thesis covers the two-photon decay of the 11 2 − isomer in 137 Ba. Clear evidence of this exotic decay mode is found, which opens up the possibility to use the twophoton decay probability as a general tool to investigate the structure of atomic nuclei. Details on the experiment are given, and the major challenges to successfully perform this difficult experiment are outlined. The two-photon decay experiment was conducted with the new LaBr 3 -detector ball which was setup from scratch in the framework of this thesis. The properties and performance of this powerful detector system -consisting of 18 large LaBr 3 -detectors -are discussed.Furthermore, proton scattering at 200 MeV has been performed on the nuclei 92,94 Zr, 94,96 Mo and 70 Zn. The measured cross sections are compared to calculations in the framework of the Quasi-Particle Phonon Model (QPM). Conclusions about the validity of the QPM results are drawn. A comparison of the excitation cross sections of the 2 + 1 states and the one-phonon quadrupole states with mixed neutron and proton symmetry (2 + ms ) allows to prove the special character of the 2 + ms states independently of electromagnetic transition strengths. The possible existence of 3 − and 4 + states with mixed proton and neutron symmetry is discussed. Furthermore the origin of collectivity of low-lying states in spherical nuclei is investigated in the QPM. Zusammenfassung

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Comprehensive studies of low-spin collective excitations in94Mo

Cited by 116 publications

References 64 publications

Relativistic Coulomb excitation of Kr88

Relativistic Coulomb excitation of Kr88

Microscopic restoration of proton-neutron mixed symmetry in weakly collective nuclei

The Two-Photon Decay of the 11-/2 Isomer of 137Ba and Mixed-Symmetry States of 92,94Zr and 94Mo

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