scholarly journals Spin-multipole nuclear matrix elements in thepnquasiparticle random-phase approximation: Implications forβandββhalf-lives

2017 ◽  
Vol 95 (1) ◽  
Author(s):  
Joel Kostensalo ◽  
Jouni Suhonen
Keyword(s):  
Nuclear Matrix ◽  
Random Phase Approximation ◽  
Random Phase ◽  
Phase Approximation ◽  
Matrix Elements

scholarly journals Estimation of nuclear matrix elements of double-$$\varvec{\beta }$$ decay from shell model and quasiparticle random-phase approximation

2021 ◽  
Vol 136 (9) ◽  
Author(s):  
J. Terasaki ◽  
Y. Iwata
Keyword(s):  
Shell Model ◽  
Nuclear Matrix ◽  
Single Particle ◽  
Random Phase Approximation ◽  
Random Phase ◽  
Nuclear Matrix Element ◽  
Phase Approximation ◽  
Quasiparticle Random Phase Approximation ◽  
Calculation Results ◽  
The Many

AbstractThe nuclear matrix element (NME) of neutrinoless double-$$\beta $$ β ($$0\nu \beta \beta $$ 0 ν β β ) decay is an essential input for determining the neutrino effective mass, if the half-life of this decay is measured. Reliable calculation of this NME has been a long-standing problem because of the diversity of the predicted values of the NME, which depends on the calculation method. In this study, we focus on the shell model and the QRPA. The shell model has a rich amount of the many-particle many-hole correlations, and the quasiparticle random-phase approximation (QRPA) can obtain the convergence of the calculation results with respect to the extension of the single-particle space. It is difficult for the shell model to obtain the convergence of the $$0\nu \beta \beta $$ 0 ν β β NME with respect to the valence single-particle space. The many-body correlations of the QRPA may be insufficient, depending on the nuclei. We propose a new method to phenomenologically modify the results of the shell model and the QRPA compensating for the insufficiencies of each method using the information of other methods in a complementary manner. Extrapolations of the components of the $$0\nu \beta \beta $$ 0 ν β β NME of the shell model are made toward a very large valence single-particle space. We introduce a modification factor to the components of the $$0\nu \beta \beta $$ 0 ν β β NME of the QRPA. Our modification method yields similar values of the $$0\nu \beta \beta $$ 0 ν β β NME for the two methods with respect to $$^{48}$$ 48 Ca. The NME of the two-neutrino double-$$\beta $$ β decay is also modified in a similar but simpler manner, and the consistency of the two methods is improved.

scholarly journals Number-conserving random phase approximation with analytically integrated matrix elements

1990 ◽  
Vol 41 (1) ◽  
pp. 284-297 ◽  
Author(s):  
M. Kyotoku ◽  
K. W. Schmid ◽  
F. Grümmer ◽  
Amand Faessler
Keyword(s):  
Random Phase Approximation ◽  
Random Phase ◽  
Phase Approximation ◽  
Matrix Elements

scholarly journals Study of the exotic μ-e conversion in nuclei using RQRPA

2020 ◽  
Vol 9 ◽  
pp. 1
Author(s):  
Zhongzhu Ren ◽  
A. Faessler ◽  
T. S. Kosmas
Keyword(s):  
Periodic Table ◽  
Transition Matrix ◽  
Random Phase Approximation ◽  
Random Phase ◽  
Pauli Principle ◽  
Phase Approximation ◽  
Matrix Elements ◽  
Quasiparticle Random Phase Approximation ◽  
Electron Conversion ◽  
Transition Matrix Elements

The neutrinoless muon-to-electron conversion in nuclei is studied by using the renormalized quasiparticle random-phase approximation (RQRPA). This generalization of RPA is more reliable for the extremely small (μ-,e-) transition matrix elements than the ordinary QRPA because it restores the Pauli principle to a large extent. We apply the method to a set of nuclei throughout the periodic table, but we specifically investigate the 48Ti and 208Pb nuclei which are currently used as stopping targets at the PSI μ-e conversion experiments with the SINDRUM II spectrometer.

scholarly journals Comparative Analysis of Nuclear Matrix Elements of 0νβ+β+ Decay and Muon Capture in 106Cd

2021 ◽  
Vol 9 ◽  
Author(s):  
Lotta Jokiniemi ◽  
Jouni Suhonen ◽  
Jenni Kotila
Keyword(s):  
Nuclear Matrix ◽  
Random Phase Approximation ◽  
Random Phase ◽  
Particle Interaction ◽  
Double Beta Decay ◽  
Muon Capture ◽  
Matrix Elements ◽  
Β Decay ◽  
Quasiparticle Random Phase Approximation ◽  
First Time

Comparative analyses of the nuclear matrix elements (NMEs) related to the 0νβ+β+ decay of 106Cd to the ground state of 106Pd and the ordinary muon capture (OMC) in 106Cd are performed. This is the first time the OMC NMEs are studied for a nucleus decaying via positron-emitting/electron-capture modes of double beta decay. All the present calculations are based on the proton-neutron quasiparticle random-phase approximation with large no-core single-particle bases and realistic two-nucleon interactions. The effect of the particle-particle interaction parameter gpp of pnQRPA on the NMEs is discussed. In the case of the OMC, the effect of different bound-muon wave functions is studied.

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