How can the 0+ states be affected by pairingfluctuations?

energies of the excited 0+ states can be affected by adding pairingfluctuations [103] and/or quasiparticle excitations explicitly [104].

What is the mixing angle for the 0+ states in 42Ca?

The calculated mixing angle for the 0+ states, cos2(θ0) = 0.88(4), indicates that 0+ states in 42Ca are weakly mixed, and is consistent with the024326-13K.

What is the significance of the contribution of the single loop to the Q3 cos?

It should be noted that the contribution of this single loop is close to the value of the entire 〈Q3 cos(3δ)〉 invariant, with all other contributions cancelling out to some extent; this is especially true for the invariants calculated using experimental values of E2 matrix elements, and those resulting from LSSM calculations.

How many ps was the lifetime of the 0+2 state at 1837 ?

The lifetime of the 0+2 state at 1837 keV was determined in a p−γ coincidence measurement performed using a direct electronic timing technique following a 42Ca(p,p′γ ) reaction [77] to be equal to 558(8) ps.

What is the effect of the introduction of a level on the observed excitation pattern?

The introduction of such a level does not affect the observed excitation pattern, as low-energy Coulomb excitation proceeds predominantly via E2 transitions; it, however, accounts for the alternative decay path of the 0+2 state.

How can the authors extract the quadrupole deformation parameters?

the quadrupole deformation parameters can be extracted using the E2 sum rules, proposed by Kumar [93], as detailed in Sec. IV D.

What is the effect of the loops on the Q2 invariant?

As shown in Table XIII, the contributions of the loops involving the 3+1 and 4 + 3 states bring less than 3% to the total 〈Q2〉 values, and therefore the authors expect the systematic error related to noncompleteness of the sum over intermediate states to be lower than the statistical error on the invariant.

What is the description of the shape coexistence of a spherical ground?

A consistent description of the shape coexistence of a spherical ground state, exhibiting large fluctuations in the β-γ plane, and a rigid superdeformed sideband in 42Ca could be achieved by performing sophisticated state-of-the-art theoretical calculations in the framework of the large scale shell-model and beyondmean-field approach.

What is the quadrupole moment of the 2+1 state in 42Ca?

The sideband based on the 0+2 state in42Ca seems to correspond to the [4,3]a configuration in Ref. [116], predicted to appear at about 1 MeV excitation energy and to have a transitional quadrupole moment Qt of about 1.5 e b [as compared to the experimental value of 1.13(10) e b].

What are the uncertainties used to calculate the uncertainty of shape parameters in Sec. IV D?

Their uncertainties, used for example to calculate the uncertainties of shape parameters in Sec. IV D, are calculated from the024326-9K.

Why are the angular distributions more meaningful than the absolute cross sections?

The angular distributions are in this case more meaningful than the absolute cross sections, and unfortunately, due to the much lower statistics, no conclusion can be drawn from those measured for the 197Au target.

How is the contribution to Q3 cos(3) calculated?

This is confirmed by the theoretical calculations, that predict it to be on the level of 5–10% of the strongest contribution to 〈Q3 cos(3δ)〉 for both the 0+1 and 0 + 2 states.

Open AccessJournal Article10.1103/PHYSREVC.97.024326

Quadrupole collectivity in Ca 42 from low-energy Coulomb excitation with AGATA

K. Hadynska-Klek, +109 more

- 21 Feb 2018

- Physical Review C

- Vol. 97, Iss: 2, pp 024326

TL;DR: A Coulomb-excitation experiment to study electromagnetic properties of Ca42 was performed using a 170-MeV calcium beam from the TANDEM XPU facility at INFN Laboratori Nazionali di Legnaro as discussed by the authors.

Abstract: A Coulomb-excitation experiment to study electromagnetic properties of Ca42 was performed using a 170-MeV calcium beam from the TANDEM XPU facility at INFN Laboratori Nazionali di Legnaro. γ rays from excited states in Ca42 were measured with the AGATA spectrometer. The magnitudes and relative signs of ten E2 matrix elements coupling six low-lying states in Ca42, including the diagonal E2 matrix elements of 21+ and 22+ states, were determined using the least-squares code gosia. The obtained set of reduced E2 matrix elements was analyzed using the quadrupole sum rule method and yielded overall quadrupole deformation for 01,2+ and 21,2+ states, as well as triaxiality for 01,2+ states, establishing the coexistence of a weakly deformed ground-state band and highly deformed slightly triaxial sideband in Ca42. The experimental results were compared with the state-of-the-art large-scale shell-model and beyond-mean-field calculations, which reproduce well the general picture of shape coexistence in Ca42.

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Most frequently asked questions

1. What have the authors contributed in "Physical review c 97, 024326 (2018) quadrupole collectivity in ca from low-energy coulomb excitation with agata" ?

In this paper, the authors proposed a method to solve the problem of how to find the minimum number of atoms in a set of dimensions.

2. What is the quadrupole deformation parameter of the total system?

In the AMD-GCM approach [115] the Gogny D1S force was used as the effective interaction and the basis wave functions of the GCM were obtained via the energy variation with two types of constraints: the quadrupole deformation parameter of the total system, β, and the distance between the α and 38Ar clusters.

3. What was the kinematic information used to correct the energies of ray?

The kinematic information from the position-sensitive detectors of the DANTE array was used to Doppler correct the energies of γ rays depopulating Coulomb-excited states in 42Ca.

4. What are the weaker lines at 376, 1674, and 2048 keV?

In addition to the transitions resulting from Coulomb excitation of 42Ca and lead isotopes, weaker lines at 376, 1674, and 2048 keV were observed.

FIG. 6. The γ -γ spectrum gated on the 570-keV γ -ray transition in 207Pb. The 373-keV γ -ray line originating from 43Ca is shown.

TABLE IX. β deformation parameter and the γ angle calculated using the Davydov-Filipov model, CHFSM, and Kumar-Cline sum rules, compared to the experimental values obtained from the sum rules (Tables XI and XII).

TABLE VII. Quadrupole properties of the 2+2 and 2 + 3 states in 42Ca, obtained in the present shell-model calculation.

FIG. 11. Experimental and theoretical 〈Q2〉 invariants for the 0+1,2 and 2+1,2 states in 42Ca.

TABLE XII. Experimental and theoretical 〈Q4〉 invariants (104 e4 fm8) and 〈cos(3δ)〉 values, calculated from 〈Q3 cos(3δ)〉 as in Refs. [111,112].

FIG. 7. The γ -ray spectrum collected in the 12C+ 32S experiment, gated on the 328-keV transition deexciting 4+1 state in 42Ca.

Citations

Transition probability from the ground to the first-excited 2^+ state of even-even nuclides

S. Raman, +2 more

- 01 Apr 2001

TL;DR: In this paper, the reduced electric quadrupole transition probability, B(E2)↑, from the ground state to the first-excited 2+ state of even-even nuclides are given in Table I.

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955

•Journal Article•10.1088/1361-6471/AADEBD

Mean field and beyond description of nuclear structure with the Gogny force: A review

L. M. Robledo, +3 more

- 06 Jul 2018

- arXiv: Nuclear Theory

TL;DR: The Gogny force is a referent in the theoretical description of nuclear structure phenomena and its phenomenological character manifests in a simple analytical form that allows for implementations of techniques both at the mean field and beyond all over the nuclide chart as mentioned in this paper.

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An experimental view on shape coexistence in nuclei

Emyr Clement, +2 more

- 01 May 2022

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TL;DR: In this article , the authors provide an overview of the experimental investigations of shape coexistence, focusing on those regions of the nuclear chart that have been the most actively investigated within the past decade.

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•Journal Article•10.1088/1361-6471/AADEBD

Mean field and beyond description of nuclear structure with the Gogny force: a review

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- 01 Jan 2019

- Journal of Physics G

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The neutron-rich edge of the nuclear landscape: Experiment and theory.

Frédéric Nowacki, +2 more

- 01 Sep 2021

- Progress in Particle and Nuclear Physics

TL;DR: In this article, the authors describe the experimental facilities and methods which make it possible to produce and measure the properties of the extreme neutron-rich nuclei, and develop the theoretical framework that predicts and explains these properties; the shell model approach with large-scale configuration interaction (mixing) SM-CI, with special emphasis in the competition between the spherical mean field and the nuclear correlations (mainly pairing and quadrupole-quadrupole).

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References

•Journal Article•10.1098/RSPA.1937.0142

Stability of Polyatomic Molecules in Degenerate Electronic States. I. Orbital Degeneracy

H. A. Jahn, +1 more

- 15 Jul 1937

- Proceedings of The Royal Society A: Math...

TL;DR: In this paper, it was shown that if the total electronic state of orbital and spin motion is degenerate, then a non-linear configuration of the molecule will be unstable unless the degeneracy is the special twofold one (discussed by Kramers 1930) which can occur only when the molecule contains an odd number of electrons.

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Journal Article•10.1006/ADND.2001.0858

Transition probability from the ground to the first-excited 2+ state of even–even nuclides

S. Raman, +2 more

- 01 Jan 1987

- Atomic Data and Nuclear Data Tables

TL;DR: In this paper, the reduced electric quadrupole transition probability, B(E2)↑, from the ground state to the first-excited 2+ state of even-even nuclides are given in Table I.

...read moreread less

1.7K

Journal Article•10.1016/0167-7977(88)90005-6

Coupled reaction channels calculations in nuclear physics

Ian J. Thompson

- 01 Apr 1988

- Computer Physics Reports

TL;DR: In this article, the components and methods of a comprehensive code for coupled reaction channels calculations in nuclear physics are described, which are common to the modelling of reactions induced by light and medium mass ions, and which are sufficient to calculate the effects of successive processes to any order.

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•Journal Article•10.1103/REVMODPHYS.77.427

The shell model as a unified view of nuclear structure

E. Caurier, +4 more

- 16 Jun 2005

- Reviews of Modern Physics

TL;DR: In this article, the Lanczos tridiagonal construction has been used to diagonalize matrices in determinantal spaces of dimensionality up to 10^9 using the Shell Model.

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Journal Article•10.1016/0029-5582(58)90153-6

Rotational states in even atomic nuclei

A.S. Davydov, +1 more

- 01 Sep 1958

- Nuclear Physics

TL;DR: In this paper, a theory of the energy states and the electromagnetic transitions between them for nuclei which do not possess axial symmetry was developed and the reduced probabilities for E2 and M1 transitions between various rotational states were computed.

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Quadrupole collectivity in Ca 42 from low-energy Coulomb excitation with AGATA

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AI Agents for this Paper

Most frequently asked questions

1. What have the authors contributed in "Physical review c 97, 024326 (2018) quadrupole collectivity in ca from low-energy coulomb excitation with agata" ?

2. What is the quadrupole deformation parameter of the total system?

3. What was the kinematic information used to correct the energies of ray?

4. What are the weaker lines at 376, 1674, and 2048 keV?

5. How can the 0+ states be affected by pairingfluctuations?

6. What is the mixing angle for the 0+ states in 42Ca?

7. What is the significance of the contribution of the single loop to the Q3 cos?

8. How many ps was the lifetime of the 0+2 state at 1837 ?

9. What is the effect of the introduction of a level on the observed excitation pattern?

10. How can the authors extract the quadrupole deformation parameters?

11. What is the effect of the loops on the Q2 invariant?

12. What is the description of the shape coexistence of a spherical ground?

13. What is the quadrupole moment of the 2+1 state in 42Ca?

14. What are the uncertainties used to calculate the uncertainty of shape parameters in Sec. IV D?

15. Why are the angular distributions more meaningful than the absolute cross sections?

16. How is the contribution to Q3 cos(3) calculated?

Figures

Citations

Transition probability from the ground to the first-excited 2^+ state of even-even nuclides

Mean field and beyond description of nuclear structure with the Gogny force: A review

An experimental view on shape coexistence in nuclei

Mean field and beyond description of nuclear structure with the Gogny force: a review

The neutron-rich edge of the nuclear landscape: Experiment and theory.

References

Stability of Polyatomic Molecules in Degenerate Electronic States. I. Orbital Degeneracy

Transition probability from the ground to the first-excited 2+ state of even–even nuclides

Coupled reaction channels calculations in nuclear physics

The shell model as a unified view of nuclear structure

Rotational states in even atomic nuclei

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