Recent Nuclear Structure Studies in Rapidly Rotating Nuclei

Garrett, J.D.; Hagemann, G.B.; Herskind, B.

doi:10.1146/annurev.ns.36.120186.002223

Cited by 59 publications

(37 citation statements)

References 67 publications

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“…4). This behaviour has been generally observed in well deformed nuclei [16], and has suggested that the transitions in the moving bump originate from SD states, since such a bump should not be expected from ND spherical states, and one does not observe it in coincidence with transitions in the more collective triaxial well of 143 Eu [17]. Angular anisotropies, moment of inertia determination and lifetimes analysis have confirmed that the bump originates from highly collective rotationally damped E2 transitions generated by SD states [12].…”

Section: The Super-deformed Quasi-continuum In 14eusupporting

confidence: 67%

The rotational quasi-continuum in specific configurations: high-K states and superdeformation

et al. 1997

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The analysis of the fluctuations of the counts of unresolved γ-γ energy spectra can extend our knowledge of the rotational motion at high angular momentum and excitation energy above the yrast band. Detailed studies of the rotational quasi-continuum built on specific intrinsic nuclear configurations are here discussed. First, the validity of the K-selection rules in the quasi-continuum region is investigated in the case of the normal deformed nucleus 163 Er. The γ cascades feeding into low-K and high-K bands are analyzed studying variance and covariance of the spectrum fluctuations. Low-K bands are found to be fed by a much larger effective number of cascades than high-K bands, while the covariance between pairs of gated spectra shows that the cascades feeding into low-K bands are different from those feeding into high-K bands. These findings suggest a persistence of K-selection rules in the region of excitation energy and angular momentum probed by the rotational decay of 163 Er. As a second case, the existence of a rotational quasi-continuum in the super deformed well of 143 Eu is discussed. An intense bump of rotationally correlated transitions is observed to develop as function of fold in the high spin region of gated spectra. Fold distribution, angular anisotropies, moment of inertia and life time show that the bump consists of fully damped super deformed transitions. This gives experimental evidence of damped rotational motion up to several MeV excitation energy above the super deformed yrast line.

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Section: The Super-deformed Quasi-continuum In 14eusupporting

confidence: 67%

The rotational quasi-continuum in specific configurations: high-K states and superdeformation

et al. 1997

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“…The functions G(r, r ′ , ε) and F + (r, r ′ , ε) are the Fourier transforms of the Green's functions 4) where Φ N and Φ N +2 are the eigenfunctions of the ground state of a system of N and N + 2 interacting particles, ψ + and ψ are creation and annihilation operators in the Heisenberg representation, T is the time ordering operator, and ε F is the Fermi energy (the chemical potential of the system). The contour C consists of the real axis and an infinite semicircle in the upper half-plane.…”

Section: Cranked Gor'kov Equationsmentioning

confidence: 99%

“…[3] the disappearance of static pairing leads to a change of the excitation spectrum, from the quasiparticle to the particle-hole spectrum. Unfortunately, the application of this criterion to normal deformed (ND) bands [3,4,5] shows that this method is not free from ambiguities.…”

Section: Introductionmentioning

confidence: 99%

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Superfluid-to-normal phase transition and extreme regularity of superdeformed bands

Pavlichenkov

2002

Phys. Atom. Nuclei

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We derive the exact semiclassical expression for the second inertial parameter B for the superfluid and normal phases. Interpolation between these limiting values shows that the function B(I) changes sign at the spin I c , which is critical for a rotational spectrum. The quantity B turns out to be a sensitive measure of the change in static pairing correlations. The superfluid-to-normal transition reveals itself in the specific variation of the ratio B/A versus spin I with the plateau characteristic of the normal phase. We find this dependence to be universal for normal deformed and superdeformed bands. The long plateau with a small value B/A ∼ A −8/3 explains the extreme regularity of superdeformed bands.

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“…However, they are very complicated and lose simplicity of the model. On the other hand, by taking into account the effect of rotation unperturbatively, the mean-field theory has been extended in the rotating frame: The cranking model or the Cranked Shell Model (CSM) [5], which is simple and yet microscopic, has been successfully applied to understand various high-spin phenomena [6] such as backbending of moment of inertia. Recently, this cranking model has been further extended in such a way to include the tilting degrees of freedom of rotation-axis relative to the deformed shape; the Tilted Axis Cranking (TAC) model [7,8,9] (the conventional cranking is called the Principal Axis Cranking (PAC) model, instead), which gives nice interpretations of new types of nuclear rotational motions, e.g.…”

Section: Introductionmentioning

confidence: 99%

Calculation of strongly-coupled rotational bands in terms of the tilted axis cranking model

Ohtsubo

Shimizu

2003

Nuclear Physics A

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Recently observed strongly-coupled rotational bands associated with the ν [505] IntroductionBohr-Mottelson's strong-coupling model [1] is the first pioneering work which is capable to describe interplay between the collective and the single-particle rotational motions in well-deformed nuclei. It successfully reproduce both the energy spectra and the electromagnetic transition properties of rotational bands in odd nuclei. It is, however, of phenomenological nature since essential quantities like the moment of inertia and the quadrupole moment are model-parameters and are adjusted in comparison with experimental data. One has to combine it with a more microscopic model such as the Nilsson single-particle model. Another drawback of the model is that it is based on the adiabatic assumption of the collective rotation and the application to the high angular momentum regime is not straightforward. The particle-rotor model [1, 2] is a possible means to extend the idea by lifting the adiabatic assumption and including the effect of Coriolis coupling by exact diagonalization, although it is still semi-phenomenological in the sense that the macroscopic "rotor" part is explicitly introduced. Nowadays, fully microscopic approaches are available, for example, the variation after full angular momentum projection base on the generalized mean-field [3] and the projected shell model [4]. However, they are very complicated and lose simplicity of the model. On the other hand, by taking into account the effect of rotation unperturbatively, the mean-field theory has been extended in the rotating frame: The cranking model or the Cranked Shell Model (CSM) [5], which is simple and yet microscopic, has been successfully applied to understand various high-spin phenomena [6] such as backbending of moment of inertia. Recently, this cranking model has been further extended in such a way to include the tilting degrees of freedom of rotation-axis relative to the deformed shape; the Tilted Axis Cranking (TAC) model [7,8,9] (the conventional cranking is called the Principal Axis Cranking (PAC) model, instead), which gives nice interpretations of new types of nuclear rotational motions, e.g. the shears bands [10] and the chiral bands [9,11]. Although these cranking models treat the rotational motion in a semiclassical manner, its simplicity allows us to have a clear physical picture of various collective rotational motions, which are actually a result of the complex nuclear many-body problem.The purpose of the present paper is two folds: The first is to give a clear relationship between the strong-coupling model and the TAC model. The second is to apply the TAC model to the 1

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Recent Nuclear Structure Studies in Rapidly Rotating Nuclei

Cited by 59 publications

References 67 publications

The rotational quasi-continuum in specific configurations: high-K states and superdeformation

The rotational quasi-continuum in specific configurations: high-K states and superdeformation

Superfluid-to-normal phase transition and extreme regularity of superdeformed bands

Calculation of strongly-coupled rotational bands in terms of the tilted axis cranking model

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