THE STRUCTURE OF NEUTRON-RICH 28,29Mg STUDIED THROUGH β-DECAY OF SPIN POLARIZED 28,29Na BEAMS AT TRIUMF

2010 ◽  
Vol 25 (21n23) ◽  
pp. 1972-1975 ◽  
Author(s):  
K. TAJIRI ◽  
K. KURA ◽  
M. KAZATO ◽  
M. SUGA ◽  
A. TAKASHIMA ◽  
...  
Keyword(s):  
Shell Model ◽  
Negative Parity ◽  
Β Decay ◽  
Model Calculations ◽  
Spin Polarized ◽  
Γ Rays ◽  
Pf Shell ◽  
Coincidence Measurements

The level structures of 28 Mg and 29 Mg have been investigated by the β-decay of spin-polarized28 Na and 29 Na at ISAC, TRIUMF. The detailed β-γ and γ-γ coincidence measurements were performed. New γ rays and β transitions were observed both in 28 Mg and 29 Mg . We have succeeded in assigning spins and parities of many levels in 28 Mg and 29 Mg . Comparison with shell model calculations using USD Hamiltonian suggest that the structure of 28 Mg and 29 Mg are well explained in the sd-shell configurations, except for two levels at 1.095 and 1.430 MeV in 29 Mg . This suggests negative parity assignments for these levels. The evolution of sd-pf shell is discussed.

Low-lying Negative-parity Levels of 17N and 18N

1984 ◽  
Vol 37 (1) ◽  
pp. 17 ◽  
Author(s):  
FC Barker
Keyword(s):  
Shell Model ◽  
Weak Coupling ◽  
Coupling Model ◽  
Negative Parity ◽  
Positive Parity ◽  
Model Calculations

On the basis of a weak-coupling model, adjustments are made to the interactions used in the full shell model calculations of Millener in order to fit the experimental energies of the low-lying negativeparity levels of 16N and of the low-lying positive-parity levels of 180 and 190 . The predicted energies of the low-lying negative-parity levels of 17N then agree better with experiment, while those for 18N lead to suggested spin assignments for the observed levels.

scholarly journals Large Scale Shell Model Calculations of the Negative-Parity States Structure in 24Mg Nucleus

2021 ◽  
Vol 66 (4) ◽  
pp. 293
Author(s):  
A.A. Al-Sammarraie ◽  
F.A. Ahmed ◽  
A.A. Okhunov
Keyword(s):  
Shell Model ◽  
Large Scale ◽  
Transition Probabilities ◽  
Transition Probability ◽  
Energy Levels ◽  
Form Factors ◽  
Model Space ◽  
Negative Parity ◽  
Matrix Elements ◽  
Model Calculations

The negative-parity states of 24Mg nucleus are investigated within the shell model. We are based on the calculations of energy levels, total squared form factors, and transition probability using the p-sd-pf (PSDPF) Hamiltonian in a large model space (0 + 1) hW. The comparison between the experimental and theoretical states showed a good agreement within a truncated model space. The PSDPF-based calculations successfully reproduced the data on the total squared form factors and transition probabilities of the negative-parity states in 24Mg nucleus. These quantities depend on the one-body density matrix elements that are obtained from the PSDPF Hamiltonian. The wave functions of radial one-particle matrix elements calculated with the harmonic-oscillator potential are suitable to predict experimental data by changing the center-of-mass corrections.

SHAPE EVOLUTION OF HIGHLY DEFORMED 75Kr AND PROJECTED SHELL MODEL DESCRIPTION

2010 ◽  
Vol 19 (08n09) ◽  
pp. 1754-1762 ◽  
Author(s):  
YING-CHUN YANG ◽  
YANG SUN ◽  
T. TRIVEDI ◽  
R. PALIT ◽  
J. A. SHEIKH
Keyword(s):  
Shell Model ◽  
Negative Parity ◽  
Model Description ◽  
Shape Evolution ◽  
Quadrupole Moments ◽  
Projected Shell Model ◽  
Model Calculations ◽  
High Spin States ◽  
Parity Band ◽  
Insight Into

A study of recently-measured high spin states of 75 Kr is carried out by using the Projected Shell Model. Calculations are performed up to spin I = 33/2 for the positive parity band and I = 27/2 for the negative parity band. Irregularities found in moment of inertia and in the deduced transition quadrupole moments Q t of the two bands are discussed in terms of the alignment of g 9/2 protons. Our study provides an insight into the shape evolution of the well-deformed nucleus 75 kr .

scholarly journals Shell-model calculations for upper pf-shell nuclei with an effective interaction

2018 ◽  
Vol 194 ◽  
pp. 01006
Author(s):  
Kalin Drumev
Keyword(s):  
Shell Model ◽  
Effective Interaction ◽  
Model Space ◽  
Model Calculations ◽  
Energy Eigenstates ◽  
Mixed Symmetry ◽  
Symmetry Approach ◽  
Oscillator Shell ◽  
Single Oscillator ◽  
Pf Shell

Results obtained for the energy spectra and the low-lying positive-parity energy eigenstates of the upper p f -shell nuclei 64Ge and 68Se with the use of the effective interaction JUN45 are reported. We address the question of how appropriate is the possibility to construct a symmetry-adapted shell model in a single oscillator shell using a Pairing-plus-Quadrupole Hamiltonian. Specifically, we study the goodness of the symmetries pseudo SU(3) and O(6) in the structure of the energy eigenstates. Finally, we relate our results to a proposed mixed-symmetry approach which is able to simultaneously account for the presence of both the pairing and the quadrupole modes as the most important ingredients in the effective interaction while using a restricted part of the full model space.

Study of odd mass 115−125Sb isotopes with the projected shell model calculations

2017 ◽  
Vol 26 (06) ◽  
pp. 1750041 ◽  
Author(s):  
Dhanvir Singh ◽  
Arun Bharti ◽  
Amit Kumar ◽  
Suram Singh ◽  
G. H. Bhat ◽  
...  
Keyword(s):  
Shell Model ◽  
Transition Probabilities ◽  
Negative Parity ◽  
Yrast Band ◽  
Spin States ◽  
Projected Shell Model ◽  
Model Calculations ◽  
High Spin States ◽  
Reduced Transition Probabilities ◽  
First Time

The projected shell model (PSM) with the deformed single-particle states, generated by the standard Nilsson potential, is applied to study the negative-parity high spin states of [Formula: see text] nuclei. The nuclear structure quantities like band structure and back-bending in moment of inertia have been calculated with PSM method and are compared with the available experimental data. In addition, the reduced transition probabilities, i.e., B[Formula: see text] and B[Formula: see text], are also obtained for the yrast band of these isotopes for the first time by using PSM wave function. A multi-quasiparticle structure has been predicted for [Formula: see text] isotopes by the present PSM calculations.

FIRST USE OF POST-ACCELERATED ISOMERIC BEAMS FOR COULOMB EXCITATION STUDIES OF ODD-ODD NUCLEI AROUND N=40

2006 ◽  
Vol 15 (07) ◽  
pp. 1505-1512 ◽  
Author(s):  
◽  
G. GEORGIEV ◽  
I. STEFANESCU ◽  
D. L. BALABANSKI ◽  
P. BUTLER ◽  
...  
Keyword(s):  
Shell Model ◽  
Nuclear Structure ◽  
Large Scale ◽  
Coulomb Excitation ◽  
Model Calculations ◽  
Preliminary Results ◽  
Γ Rays ◽  
Isomeric States

We report on the first use of post-accelerated radioactive isomeric beams. Long-lived isomeric states in 68 Cu and 70 Cu have been produced and separated at ISOLDE, CERN. Subsequently they were post-accelerated to 2.86 MeV/u and sent to a target in the center of the MINIBALL spectrometer, used for the detection of the γ-rays of interest. The preliminary results from the Coulomb excitation of the Iπ=6-, 1+ states in 68 Cu and the Iπ=6- one in 70 Cu , compared to a large-scale shell model calculations, hint the importance of the excitations across the Z=28 gap for the understanding of the nuclear structure in the neutron-rich N=40 region.

Resonances in the 15N(α,γ)19F Reaction Between Eα = 1.68 and 2.72 MeV

1972 ◽  
Vol 50 (20) ◽  
pp. 2428-2443 ◽  
Author(s):  
D. W. O. Rogers ◽  
R. P. Beukens ◽  
W. T. Diamond
Keyword(s):  
Shell Model ◽  
Weak Coupling ◽  
Coupling Model ◽  
Branching Ratios ◽  
Negative Parity ◽  
Angular Distributions ◽  
Model Calculations ◽  
Spin Parity ◽  
The Third

Using the 15N(α,γ)19F reaction, the properties of 6 levels between 5.3 and 6.2 MeV in 19F have been studied. In conjunction with previously reported restrictions on spins for these levels, measurements of branching ratios, radiative widths, and angular distributions have been used to make the following spin–parity assignments; 5618 keV, 3/2−; 5938 keV, 1/2+; 6070 keV, 7/2+; 6088 keV, 3/2−; 6160 keV, 7/2−. The properties of these levels and that at 5336 keV have been compared in detail to the various shell model calculations done for 19F. The properties of the third Jπ = 7/2+ level at 6.07 MeV can be used to clear up some of the confusion caused by the first two Jπ = 7/2+ levels in 19F and the properties of the Jπ = 3/2− levels confirm the fact that the weak coupling model does not explain the negative parity states outside the K = 1/2− band.

scholarly journals Gamow-Teller transitions of neutron-rich N = 82, 81 nuclei by shell-model calculations

2021 ◽  
Author(s):  
Noritaka Shimizu ◽  
Tomoaki Togashi ◽  
Yutaka Utsuno
Keyword(s):  
Shell Model ◽  
Large Scale ◽  
Β Decay ◽  
Excitation Energies ◽  
Pauli Blocking ◽  
Model Calculations ◽  
Model Hamiltonian ◽  
R Process ◽  
Gamow Teller ◽  
Valence Proton

Abstract β-decay half-lives of neutron-rich nuclei around N = 82 are key data to understand the r-process nucleosynthesis. We performed large-scale shell-model calculations in this region using a newly constructed shell-model Hamiltonian, and successfully described the low-lying spectra and half-lives of neutron-rich N = 82 and N = 81 isotones with Z = 42 − 49 in a unified way. We found that their Gamow-Teller strength distributions have a peak in the low-excitation energies, which significantly contributes to the half-lives. This peak, dominated by ν0g7/2 → π0g9/2 transitions, is enhanced on the proton deficient side because the Pauli-blocking effect caused by occupying the valence proton 0g9/2 orbit is weakened.

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