Level density of the sd-nuclei—Statistical shell-model predictions

Starting from an appropriate decomposition of the level density into an average and fluctuating part, we studied the energy level fluctuations of an ensemble defined by two-body random Hamiltonians. A detailed analysis of several spectrally averaged fluctuation measures shows close agreement with the predictions of the Gaussian orthogonal ensemble (GOE). This confirms earlier indications that, except for noninteracting particles, fluctuation measures are insensitive to the rank of the interaction. Further, analysis of spectra obtained from realistic nuclear interactions agrees well with the GOE indicating that specific properties of the Hamiltonian have little or no influence on fluctuations. These results, therefore, strengthen our belief in the "universality" of GOE fluctuations.

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Nuclear Shell Model and Level Density

Compound-Nuclear Reactions - Springer Proceedings in Physics ◽

10.1007/978-3-030-58082-7_14 ◽

2020 ◽

pp. 123-131

Author(s):

Vladimir Zelevinsky ◽

Sofia Karampagia

Keyword(s):

Shell Model ◽

Level Density ◽

Nuclear Shell Model ◽

Nuclear Shell

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Stochastic estimation of level density in nuclear shell-model calculations

EPJ Web of Conferences ◽

10.1051/epjconf/201612202003 ◽

2016 ◽

Vol 122 ◽

pp. 02003 ◽

Cited By ~ 1

Author(s):

Noritaka Shimizu ◽

Yutaka Utsuno ◽

Yasunori Futamura ◽

Tetsuya Sakurai ◽

Takahiro Mizusaki ◽

...

Keyword(s):

Shell Model ◽

Level Density ◽

Stochastic Estimation ◽

Nuclear Shell Model ◽

Model Calculations ◽

Nuclear Shell

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Spectroscopic Study of 32S Through the 31P(d,n)32S Reaction

Canadian Journal of Physics ◽

10.1139/p74-173 ◽

1974 ◽

Vol 52 (14) ◽

pp. 1288-1294 ◽

Cited By ~ 5

Author(s):

A. H. Hussein ◽

G. C. Neilson ◽

W. J. McDonald ◽

W. K. Dawson

Keyword(s):

Spectroscopic Study ◽

Shell Model ◽

Cross Sections ◽

Differential Cross ◽

Time Of Flight ◽

Angular Distributions ◽

Absolute Differential ◽

Spectroscopic Factors ◽

Model Predictions ◽

Theoretical Predictions

The 31P(d,n)32S reaction has been studied at deuteron energies of 4.0 and 5.45 MeV. Neutron energies were measured by time of flight. Absolute differential cross sections of seven levels in 32S have been measured and compared with the theoretical predictions of both the DWBA and compound statistical theories. Analysis of the angular distributions yielded lP values and absolute spectroscopic factors. These results have been compared with those from other experiments and shell model predictions.

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STUDIES IN THE DECAY OF THE ACTIVE DEPOSIT OF ACTINIUM: I. ALPHA–GAMMA ANGULAR CORRELATION IN THE DECAY OF Bi211 (AcC)

Canadian Journal of Physics ◽

10.1139/p64-164 ◽

1964 ◽

Vol 42 (9) ◽

pp. 1798-1812 ◽

Cited By ~ 8

Author(s):

C. R. Cothern ◽

R. D. Connor

Keyword(s):

Shell Model ◽

Angular Correlation ◽

Angular Momenta ◽

Mixing Parameters ◽

Isotropic Distribution ◽

Model Predictions ◽

Γ Ray ◽

Polarization Correlation ◽

Do So ◽

Isotropy Condition

The α–γ angular correlation of the cascade Bi211(α, 6.27 MeV)Tl207*(γ, 350 keV)Tl207 has been found to be isotropic to within [Formula: see text].Accepting the spin and parity of the ground state of Tl207as 1/2+, a search was made for all reasonable spins and angular momenta, pure and mixed, which could yield an isotropic correlation. Shell-model predictions and other situations have been examined. No case of unmixed α-, unmixed γ-angular momenta satisfies the isotropy condition. Many other cases are found which do so, but only with the spin and parity of the excited state of Tl207 taken as 3/2+. It has been shown that 5/2+ does not yield an isotropic correlation. With one radiation mixed and the other pure, there are eight possible combinations which fit the observations. With both radiations mixed, there is an infinity of combinations of the two mixing parameters which lead to an isotropic distribution. The αk value of the 350-keV transition (0.175 ± 0.017) shows the γ ray in question to be 76% M1 and 24% E2. The present work is consistent with only one of the two possibilities given by Gorodetzky et al. (1962) from polarization–correlation work. Accepting this additional evidence it would appear that the most plausible interpretation is that of shell-model spins and parities with both radiations mixed, α—(λ = 3, 5), γ—(76% M1, 24% E2).

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Shell-model predictions for electromagnetic properties ofN=50nuclei

Physical Review C ◽

10.1103/physrevc.38.2849 ◽

1988 ◽

Vol 38 (6) ◽

pp. 2849-2859 ◽

Cited By ~ 14

Author(s):

Xiangdong Ji ◽

B. H. Wildenthal

Keyword(s):

Shell Model ◽

Electromagnetic Properties ◽

Model Predictions

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Shell model predictions for19N(β−)19O

Physical Review C ◽

10.1103/physrevc.38.935 ◽

1988 ◽

Vol 38 (2) ◽

pp. 935-939 ◽

Cited By ~ 15

Author(s):

E. K. Warburton

Keyword(s):

Shell Model ◽

Model Predictions

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An Investigation of Odd Parity States in 32S

Canadian Journal of Physics ◽

10.1139/p74-130 ◽

1974 ◽

Vol 52 (11) ◽

pp. 950-958 ◽

Cited By ~ 8

Author(s):

H. Grawe ◽

J. E. Cairns ◽

M. W. Greene ◽

J. A. Kuehner

Keyword(s):

Shell Model ◽

Excited States ◽

Linear Polarization ◽

Doppler Shift ◽

Polarization Measurement ◽

Angular Distributions ◽

Resonance States ◽

Mixing Ratios ◽

Model Predictions

States in 32S have been populated using the 31P(p,γ) reaction at the Ep = 895, 1438, and 1583 keV resonances. Angular distributions, a linear polarization measurement, and the results from the 32S(α,α′) reaction at 180° yielded the following spin and/or parity assignments for bound levels Jπ(6.62) = 4−, Jπ(6.76) = 3−, 4+, 5−, Jπ(6.85) = 3−, 4+, and Jπ(7.95) = 3, 4, 5−, and for resonance states J(10.26) = 4 and J(10.40) = 4. The γ decay of selected excited states has been studied and mixing ratios were obtained for the strongest branches. Doppler shift measurements yielded lifetimes of 810 (−250, +350) fs, > 300 fs and 110 (−40, +60) fs for the states at 6.62, 6.76, and 7.95 MeV respectively. The results are discussed and compared with shell model predictions.

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