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.

scholarly journals Shell Model Calculations for 18,19,20O Isotopes by Using USDA and USDB Interactions

2018 ◽  
Vol 63 (3) ◽  
pp. 189 ◽  
Author(s):  
A. K. Hasan
Keyword(s):  
Shell Model ◽  
Empirical Data ◽  
Transition Probabilities ◽  
Energy Levels ◽  
Model Space ◽  
Magic Nucleus ◽  
Model Calculations ◽  
O Isotopes ◽  
Good Agreement

The shell model (SM) is used to calculate the energy levels and transition probabilities B(E2) for 18,19,20 O isotopes. Two interactions (USDA and USDB) are used in the SDPN model space. We assume that all possible many-nucleon configurations are defined by the 0d5/2, 1s1/2, and d3/2 states that are higher than in 16 O doubly magic nucleus. The available empirical data are in a good agreement with theoretical energy levels predictions. Spins and parities were affirmed for new levels, and the transition probabilities B(E2; ↓) are predicted.

scholarly journals Shell model calculations in the A ~ 100 mass region

2020 ◽  
Vol 6 ◽  
pp. 225
Author(s):  
P. Divari ◽  
L. D. Skouras
Keyword(s):  
Shell Model ◽  
Large Scale ◽  
Model Space ◽  
Mass Region ◽  
Matrix Elements ◽  
Model Calculations ◽  
Single Neutron ◽  
Least Squares Fit ◽  
The Matrix ◽  
Inert Core

The properties of nuclei with 39≤Ζ≤47 and Ν=51-52 are investigated in large scale shell-model calculations. The doubly closed nucleus 100Sn is selected as the reference state and the nuclei under examination are described in terms of proton holes and one up two neutrons outside the inert core. The proton holes are distributed in a model space consisting of the orbitals g9/2, p1/2, p3/2 while f5/2 is sometimes also considerd. Similary the model space for the neutron particles in­ cludes the orbitals g7/2, d5/2, d3/2, s1/2 and in certain cases h11/2. The effective two-body interaction and the matrix elements of the effective operators were deter­ mined by introducing second-order corrections to the Sussex matrix elements. The single proton holes as well as the single-neutron energies were treated as parameters which were determined by least-squares fit to the observed levels of 39≤Ζ≤47, Ν=50 and Ν=51 respectively. The results of the calculation were found to be in satisfactory agreement with experimental data and this enable us to make predictions about the properties of some exotic nuclei in the vicinity of 100Sn.

scholarly journals Shell model calculations in the A=90-98 mass region. A study of the N=51. nuclei

2020 ◽  
Vol 5 ◽  
pp. 90
Author(s):  
P. Divari ◽  
L. D. Skouras
Keyword(s):  
Shell Model ◽  
Large Scale ◽  
Model Space ◽  
Mass Region ◽  
Matrix Elements ◽  
Model Calculations ◽  
Single Neutron ◽  
Least Squares Fit ◽  
The Matrix ◽  
Inert Core

The properties of nuclei with 39 < Ζ < 47 and N=51 are investigated in large scale shell-model calculations. The doubly closed nucleus 100Sn is selected as the reference state and the nuclei under examination are described in terms of proton holes and a single neutron outside the inert core. The proton holes are distributed in a model space consisting of the orbitals g9/2, p1/2, p3/2 while f5/2 is sometimes also considerd. Similary the model space for the single neutron includes the orbitals g7/2, d5/2, d3/2, s1/2 and in certain cases h11/2. The effective two-body interaction and the matrix elements of the effective operators were determined by introducing second-order correctios to the Sussex matrix elements. The single proton holes as well as the single-neutron energies were treated as parameters which were determined by least-squares fit to the observed levels of 39 < Ζ < 47, N=50 and Ν=51 respectively. The results of the calculation were found to be in satisfactory agreement with experimental data and this enable us to make predictions about the properties of some exotic nuclei in the vicinity of 100Sn.

scholarly journals Nuclear structure study of [22,24]Ne and [24]Mg nuclei

2019 ◽  
Vol 65 (2) ◽  
pp. 159
Author(s):  
Fouad A. Majeed ◽  
And Sarah M. Obaid
Keyword(s):  
Experimental Data ◽  
Shell Model ◽  
Nuclear Structure ◽  
Transition Probabilities ◽  
Form Factors ◽  
Model Space ◽  
High Energy ◽  
Core Polarization ◽  
Model Calculations ◽  
The Core

Shell model calculations based on large basis has been conducted to study the nuclear structure of $^{20}Ne$, $^{22}Ne$ and $^{24}Mg$ nuclei. The energy levels, inelastic electron scattering form factors and transition probabilities are discussed by considering the contribution of  configurations with high-energy beyond the model space of sd-shell model space which is denoted as the core polarization (CP) effects.~The Core polarization is considered by taking the excitations of nucleus from the $1s$ and $1p$ core orbits and also from the valence $2s$ $1d$ shell orbit in to higher shells with $4\hbar\omega$. The effective interactions $USDA$ and $USDB$ are employed with $sd$ shell model space to perform the calculation and the core polarization are calculated with $MSDI$ as residual interaction.~The calculated energy level schemes,  form factors and transition probabilities were compared with the corresponding experimental data. The effect of core polarization is found very important for the calculation of $B(C2)$, $B(C4)$ and form factors, and gives excellent results in comparison with the experimental data without including any adjustable parameters.

scholarly journals ββ DECAY AND NUCLEAR STRUCTURE

2007 ◽  
Vol 16 (02) ◽  
pp. 552-560 ◽  
Author(s):  
E. CAURIER ◽  
F. NOWACKI ◽  
A. POVES
Keyword(s):  
Shell Model ◽  
Nuclear Matrix ◽  
Large Scale ◽  
Predictive Power ◽  
Strong Impact ◽  
Matrix Elements ◽  
Model Calculations ◽  
Mode Stability ◽  
Recent Developments

The determination of accurate nuclear matrix elements for ββ decay processes is a challenge for nuclear theory and can have a strong impact in neutrino physics. Large Scale Shell Model (LSSM) calculations are among the best tools for such determination and recent developments have allowed to extend its application domains. In particular, systematic studies of nuclear matrix elements calculations have been now undertaken in this framework for most of the ββ emitters. These calculations are crucial in the determination of the most favorable emitters in the forthcoming generation of ββ experiments. The present paper focuses on the recent advances and remaining difficulties of shell model calculations for the neutrinoless mode. Stability and predictive power of the results will be discussed.

scholarly journals Shell model calculations in the A=80-100 mass region and study of double β transitions

2020 ◽  
Vol 1 ◽  
pp. 156
Author(s):  
J. Sinatkas ◽  
L. D. Skouras ◽  
D. Strottman ◽  
J. D. Vergados
Keyword(s):  
Shell Model ◽  
Satisfactory Agreement ◽  
Effective Interaction ◽  
Model Space ◽  
Mass Region ◽  
Least Square ◽  
Matrix Elements ◽  
Model Calculations ◽  
Least Square Fit ◽  
The One

The structure of the Ζ,Ν < 50 nuclei is examined in a model space consisting of the 0g9/2, 1p1/2, 1p3/2 and the 0f5/2 hole orbitals outside the doubly closed 100Sn core. The effective interaction for this model space is derived by introducing second order corrections to the Sussex matrix elements, while the one-hole energies are deduced by a least square fit to the observed levels. The results of the calculation are found to be in very satisfactory agreement with experiment for all nuclei with 38<Ζ<46 but for Ζ<38 this agreement begins to deteriorate. Such a feature possibly indicates the appearance of deformation and the breaking of the Ν=50 core. The wavefunctions of the calculation are used to determine double β matrix elements in the Ge, Se, Sr and Kr isotopes.

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.

scholarly journals Elastic transverse electron scattering form factors of 11Li exotic nucleus

2019 ◽  
Vol 12 (23) ◽  
pp. 65-72
Author(s):  
B. S. Hameed
Keyword(s):  
Shell Model ◽  
Electron Scattering ◽  
Exotic Nucleus ◽  
Form Factors ◽  
Model Space ◽  
Model Calculations ◽  
Plane Wave Born Approximation ◽  
The Difference ◽  
Elastic Transverse ◽  
Transverse Electron

        The elastic transverse electron scattering form factors have been studied for the 11Li   nucleus using the Two- Frequency Shell Model (TFSM) approach. The single-particle wave functions of harmonic-oscillator (HO) potential are used with two different oscillator parameters bcore and bhalo. According to this model, the core nucleons of 9Li nucleus are assumed to move in the model space of spsdpf. The outer halo (2-neutron) in 11Li is assumed to move in the pure 1p1/2, 1d5/2, 2s1/2 orbit. The shell model calculations are carried out for core nucleons using the spsdpf-interaction.  The elastic magnetic electron scattering of the stable 7Li and exotic 11Li nuclei are also investigated through Plane Wave Born Approximation (PWBA). It is found that the difference between the total form factors of unstable isotope (11Li halo) and stable isotope 7Li is in magnitude. The measured value of the magnetic moment is also reproduced.

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