scholarly journals Delayed Alpha Spectra from the Beta Decay of 8Li and 8B

1989 ◽  
Vol 42 (1) ◽  
pp. 25 ◽  
Author(s):  
FC Barker
Keyword(s):  
Phase Shift ◽  
Shell Model ◽  
Satisfactory Agreement ◽  
Beta Decay ◽  
Matrix Elements ◽  
R Matrix ◽  
Intruder State ◽  
Parameter Values ◽  
Gamow Teller ◽  
D Wave

Many-level R-matrix fits are made to the ()(-()( scattering d-wave phase shift and to ()(-spectra from BLi and BB ,8-decay measured by Wilkinson and Alburger (1971). With the requirement that the parameter values are the same in the fits to the phase shift and the ()(-spectra data, the best overall fits are obtained for a channel radius of about 6�5 fm, implying a broad 2+ intruder state of BBe at about 9 MeV. There is satisfactory agreement between the Gamow-Teller matrix elements extracted from the fits and shell model values.

Gamow-Teller beta decay of 29–31Na comparison with shell-model estimates

1987 ◽  
Author(s):  
P. Baumann ◽  
Ph. Dessagne ◽  
A. Huck ◽  
G. Klotz ◽  
A. Knipper ◽  
...  
Keyword(s):  
Shell Model ◽  
Beta Decay ◽  
Gamow Teller

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.

scholarly journals Constraints on Heavy Neutrino and SUSY Parameters Derived from the Study of Neutrinoless Double Beta Decay

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Andrei Neacsu ◽  
Sabin Stoica
Keyword(s):  
Phase Space ◽  
Shell Model ◽  
Beta Decay ◽  
Nuclear Matrix ◽  
Neutrinoless Double Beta Decay ◽  
Lepton Number ◽  
Double Beta Decay ◽  
Heavy Neutrino ◽  
Matrix Elements ◽  
Lepton Number Violating

New constraints on the lepton number violating (LNV) parameters are derived from the analysis of the neutrinoless double beta (0νββ) decay in the hypothesis that this process would occur through the exchange of heavy neutrinos and/or SUSY particles. For derivation, we use new values of both phase space factors (PSFs) and nuclear matrix elements (NMEs) calculated with numerical codes developed recently, as well as the most recent experimental lifetimes. The NMEs are computed with a shell model (ShM) code for 48Ca, 76Ge, and 82Senuclei, while at present similar ShM results are available only for the first nucleus. We compare our results with similar ones from literature, obtained with ShM, QRPA, and IBM-2 methods, and conclude that more results are needed for a relevant analysis on the validity of NMEs associated with these decay mechanisms.

scholarly journals Study of the double Gamow-Teller transitions using the shell model approach

2018 ◽  
Vol 194 ◽  
pp. 02003
Author(s):  
Naftali Auerbach ◽  
Minh-Loc Bui
Keyword(s):  
Shell Model ◽  
Beta Decay ◽  
Ground State ◽  
Parent Nucleus ◽  
Nuclear Matrix Element ◽  
Double Beta Decay ◽  
Teller Transition ◽  
Nuclear Shell ◽  
Gamow Teller ◽  
Model Approach

The double Gamow-Teller strength distributions in the lightest double beta-decay candidate 48Ca and its isotope 46Ca were calculated using the nuclear shell model by applying the single Gamow-Teller operator two times sequentially on the ground state of parent nucleus. The nuclear matrix element of the double Gamow- Teller transition from the ground state to the ground state that goes into the double beta decay calculation was shown as a small fraction of the total transition.

scholarly journals Gamow-Teller beta decay ofNa29and comparison with shell-model predictions

1987 ◽  
Vol 36 (2) ◽  
pp. 765-773 ◽  
Author(s):  
P. Baumann ◽  
Ph. Dessagne ◽  
A. Huck ◽  
G. Klotz ◽  
A. Knipper ◽  
...  
Keyword(s):  
Shell Model ◽  
Beta Decay ◽  
Model Predictions ◽  
Gamow Teller

Nuclear interaction matrix elements in a phase-shift approximation

1969 ◽  
Vol 47 (22) ◽  
pp. 2459-2474 ◽  
Author(s):  
M. K. Srivastava ◽  
A. M. Jopko ◽  
Donald W. L. Sprung
Keyword(s):  
Phase Shift ◽  
Shell Model ◽  
Model Calculation ◽  
Nuclear Interaction ◽  
Phase Shifts ◽  
Shell Model Calculation ◽  
Interaction Matrix ◽  
Matrix Elements ◽  
Experimental Phase ◽  
Practical Scheme

A method suggested by Elliott for calculating nuclear interaction matrix elements directly from phase shifts is developed into a practical scheme applicable to all partial waves. Matrix elements are constructed from experimental phase shifts and compared to several other calculations. A shell-model calculation of 58Ni based on these matrix elements gives results comparable to those of Kuo.

scholarly journals 2+ States of 8Be

1969 ◽  
Vol 22 (3) ◽  
pp. 293 ◽  
Author(s):  
FC Barker
Keyword(s):  
Excited State ◽  
Phase Shift ◽  
Excited States ◽  
Wave Scattering ◽  
Matrix Theory ◽  
Half Maximum ◽  
R Matrix ◽  
Particle Spectra ◽  
Scattering Phase ◽  
D Wave

Analysis by many-level R-matrix theory of the d-wave "'-'" scattering phase shift suggests the existence of broad 2+ excited states of 8Be, but their properties depend sensitively on the assumed channel radius a2. A simultaneous fit to the 9Be(p, d)8Be deuteron spectrum near the 2, 9 MeV peak requires a2 "'" 7�1 fm, while a simultaneous fit to the ",-particle spectra following 8Li and 8B p-decays requires a2 "'" 6� 7 fm. For the best overall fit with a2 = 6�75 fm, the first 2+ excited state is at 2� 84 MeV excitation energy with a width at half maximum of 1�30 MeV. It is shown that data from other reactions which appeared to give much larger widths for this level can be fitted using the same R-matrix parameters. A second 2+ excited state is obtained at about 9 MeV with a width of about 10 MeV. Properties of the narrow 2+ states at 16�6 and 16�9 MeV are also discussed.

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