scholarly journals DEFORMED SHELL MODEL RESULTS FOR TWO-NEUTRINO POSITRON DOUBLE BETA DECAY OF 84Sr

2011 ◽  
Vol 20 (08) ◽  
pp. 1723-1733 ◽  
Author(s):  
R. SAHU ◽  
V. K. B. KOTA
Keyword(s):  
Shell Model ◽  
Beta Decay ◽  
Single Particle ◽  
Double Beta Decay ◽  
Orbital Energy ◽  
Decay Modes ◽  
Fock States ◽  
Hartree Fock ◽  
Model Based ◽  
Reasonable Description

Half-lives [Formula: see text] for two-neutrino positron double beta decay modes β+ EC/ECEC are calculated for 84 Sr , a nucleus of current experimental interest, within the framework of the deformed shell model based on Hartree–Fock states employing a modified Kuo interaction in (2p3/2, 1f5/2, 2p1/2, 1g9/2) space. For a reasonable description of the spectra of 84 Sr and 84 Kr and to generate allowed GT strengths, the single particle energies of the proton and neutron 1g9/2 orbitals, relative to the 2p3/2 orbital energy, are chosen to be 3.5 MeV and 1.5 MeV for both 84 Sr and 84 Rb and 1.5 MeV and 1.5 MeV for 84 Kr . With this, the calculated half-lives for the β+ EC and ECEC modes are ~1026 yr and ~4×1024 yr respectively.

Deformed shell model results for two-neutrino double-beta decay of 82Se

2011 ◽  
Vol 89 (11) ◽  
pp. 1101-1105 ◽  
Author(s):  
R. Sahu ◽  
P.C. Srivastava ◽  
V.K.B. Kota
Keyword(s):  
Shell Model ◽  
Beta Decay ◽  
Half Life ◽  
Model Space ◽  
Spectroscopic Properties ◽  
Double Beta Decay ◽  
Hartree Fock ◽  
The Past ◽  
Quenching Factor ◽  
Reasonable Description

The half-life for two-neutrino double-beta decay has been calculated for 82Se, within the framework of the deformed shell model (DSM) based on Hartree–Fock states employing a modified Kuo interaction in 2p3/2, 1f5/2, 2p1/2, and 1g9/2 space with single particle energies (relative to a 56Ni core) for the four orbitals taken as 0.0, 0.78, 1.08, and 4.25 MeV, respectively. A reasonable description is obtained for the spectroscopic properties of yrast levels in 82Se, and similarly in the past 82Kr was studied successfully using DSM. The half-life calculated using DSM is ∼3.56 × 1020 a compared to the experimental value (0.92 ± 0.07) × 1020 a. We have also recalculated the half-life by including the 1f7/2 orbit in the preceding model space using the fpg interaction introduced by Sorlin et al. (Phys. Rev. Lett. 88, 092501 (2002)). The calculated half-life is 2.05 × 1019 a (0.58 × 1020 a if we include the quenching factor of 0.77).

scholarly journals Deformed shell model results for neutrinoless double beta decay of nuclei in A = 60 - 90 region

2015 ◽  
Vol 24 (03) ◽  
pp. 1550022 ◽  
Author(s):  
R. Sahu ◽  
V. K. B. Kota
Keyword(s):  
Shell Model ◽  
Beta Decay ◽  
Good Description ◽  
Effective Interaction ◽  
Model Space ◽  
Spectroscopic Properties ◽  
Neutrinoless Double Beta Decay ◽  
Double Beta Decay ◽  
Hartree Fock ◽  
Transition Matrix Elements

Nuclear transition matrix elements (NTME) for the neutrinoless double beta decay (Oνββ or OνDBD) of 70 Zn , 80 Se and 82 Se nuclei are calculated within the framework of the deformed shell model (DSM) based on Hartree–Fock (HF) states. For 70 Zn , jj44b interaction in 2p3/2, 1f5/2, 2p1/2 and 1g9/2 space with 56 Ni as the core is employed. However, for 80 Se and 82 Se nuclei, a modified Kuo interaction with the above core and model space are employed. Most of our calculations in this region were performed with this effective interaction. However, jj44b interaction has been found to be better for 70 Zn . The above model space was used in many recent shell model (SM) and interacting boson model (IBM) calculations for nuclei in this region. After ensuring that DSM gives good description of the spectroscopic properties of low-lying levels in these three nuclei considered, the NTME are calculated. The deduced half-lives with these NTME, assuming neutrino mass is 1 eV, are 1.1 × 1026, 2.3 × 1027 and 2.2 × 1024 yr for 70 Zn , 80 Se and 82 Se , respectively.

scholarly journals Role of Single-Particle Energies in Microscopic Interacting Boson Model Double Beta Decay Calculations

Universe ◽  
2021 ◽  
Vol 7 (3) ◽  
pp. 66
Author(s):  
Jenni Kotila
Keyword(s):  
Beta Decay ◽  
Single Particle ◽  
Field Potential ◽  
Double Beta Decay ◽  
Interacting Boson Model ◽  
Model Calculations ◽  
Single Particle Level ◽  
Particle Level ◽  
Boson Model

Single-particle level energies form a significant input in nuclear physics calculations where single-particle degrees of freedom are taken into account, including microscopic interacting boson model investigations. The single-particle energies may be treated as input parameters that are fitted to reach an optimal fit to the data. Alternatively, they can be calculated using a mean field potential, or they can be extracted from available experimental data, as is done in the current study. The role of single-particle level energies in the microscopic interacting boson model calculations is discussed with special emphasis on recent double beta decay calculations.

scholarly journals Neutrinoless Double-beta Decay Rates Around Mass 80 In The Nuclear Shell Model

2017 ◽  
Author(s):  
Kota Yanase ◽  
Naotaka Yoshinaga ◽  
Koji Higashiyama ◽  
Eri Teruya ◽  
Daisuke Taguchi
Keyword(s):  
Shell Model ◽  
Beta Decay ◽  
Neutrinoless Double Beta Decay ◽  
Decay Rates ◽  
Double Beta Decay ◽  
Nuclear Shell Model ◽  
Nuclear Shell

COLLECTIVE BANDS IN 68Se

2002 ◽  
Vol 11 (06) ◽  
pp. 531-538 ◽  
Author(s):  
K. C. TRIPATHY ◽  
R. SAHU
Keyword(s):  
Configuration Space ◽  
Single Particle ◽  
Fock States ◽  
Hartree Fock ◽  
Ground Band ◽  
Prolate Shape ◽  
Particle Orbits ◽  
Excited Band ◽  
Inert Core ◽  
Configuration Mixing

The collective bands of the N = Z nucleus 68 Se are studied within our deformed configuration mixing shell model based on Hartree–Fock states. The configuration space consists of the spherical single particle orbits 1p3/2, 0f5/2, 1p1/2 and 0g9/2 with 56 Ni as the inert core. A modified Kuo interaction for this basis space has been used in our calculation. The calculated ground band, K = 2+ excited band and the K = 5- excited band agree reasonably well with the experiment. Our calculation shows that the ground band is essentially of oblate shape and the excited K = 2+ band is of prolate shape. This is in agreement with the conclusions drawn from the recent experimental analysis.

scholarly journals Two-neutrino Double-Beta Decay within the Realistic Shell Model

2018 ◽  
Vol 1056 ◽  
pp. 012012 ◽  
Author(s):  
L Coraggio ◽  
L De Angelis ◽  
T Fukui ◽  
A Gargano ◽  
N Itaco
Keyword(s):  
Shell Model ◽  
Beta Decay ◽  
Double Beta Decay

Shell-model and QRPA treatments of double beta decay

1988 ◽  
Vol 208 (2) ◽  
pp. 187-193 ◽  
Author(s):  
J. Engel ◽  
P. Vogel ◽  
O. Civitarese ◽  
M.R. Zirnbauer
Keyword(s):  
Shell Model ◽  
Beta Decay ◽  
Double Beta Decay

Hartree–Fock and Shell-Model Studies of 56Ni

1973 ◽  
Vol 51 (7) ◽  
pp. 737-742 ◽  
Author(s):  
G. Do Dang ◽  
J. A. Rabbat
Keyword(s):  
Shell Model ◽  
Excited States ◽  
Single Particle ◽  
Critical Discussion ◽  
Hartree Fock ◽  
Model Studies

The structure of the low-lying states of 56Ni is studied in the frameworks of the Hartree–Fock theory and the shell model. Attention is focused on the choice of the single particle energies and the effect of highly excited states. It is found that the low-lying states can reasonably be described by the shell model with 1p–1h and 2p–2h excitations from the 1f7/2 level. A critical discussion of the contradictory results of previous works is made and their connection with the present work is pointed out.

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