scholarly journals An Effective Method to Accurately Calculate the Phase Space Factors forβ-β-Decay

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Andrei Neacsu ◽  
Mihai Horoi
Keyword(s):  
Phase Space ◽  
Daughter Nucleus ◽  
Good Accuracy ◽  
Recent Literature ◽  
Coulomb Field ◽  
Decay Rates ◽  
Double Beta Decay ◽  
Exact Methods ◽  
Β Decay ◽  
Energy Distributions

Accurate calculations of the electron phase space factors are necessary for reliable predictions of double-beta decay rates and for the analysis of the associated electron angular and energy distributions. We present an effective method to calculate these phase space factors that takes into account the distorted Coulomb field of the daughter nucleus, yet it allows one to easily calculate the phase space factors with good accuracy relative to the most exact methods available in the recent literature.

scholarly journals New Phase Space Calculations for β-Decay Half-Lives

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Sabin Stoica ◽  
Mihail Mirea ◽  
Ovidiu Niţescu ◽  
Jameel-Un Nabi ◽  
Mavra Ishfaq
Keyword(s):  
Phase Space ◽  
Decay Rates ◽  
Light Nuclei ◽  
Nuclear Potential ◽  
Proton Density ◽  
Β Decay ◽  
Electron Positron ◽  
Positron Decay ◽  
The Stability ◽  
New Phase

We revisit the computation of the phase space factors (PSF) involved in the positron decay and EC processes for a large number of nuclei of experimental interest. To obtain the electron/positron wave functions, we develop a code for solving accurately the Dirac equation with a nuclear potential derived from a realistic proton density distribution in the nucleus. The finite nuclear size (FNS) and screening effects are included through recipes which differ from those used in previous calculations. Comparing our results with previous calculations, performed with the same Q-values, we find a close agreement for positron decays, while, for the EC process, there are relevant differences. For the EC process, we also find that the screening effect has a notable influence on the computed PSF values especially for light nuclei. Further, we recomputed the same PSF values but using the most recent Q-values reported in literature. In several cases, the new Q-values differ significantly from the older ones, leading to large differences in the PSF values as compared with previous results. Our new PSF values can contribute to more reliable calculations of the beta-decay rates, used in the study of nuclei far from the stability line and stellar evolution.

The 2νβ−β− decay rates within Pyatov's restoration method

2017 ◽  
Vol 957 ◽  
pp. 491-512 ◽  
Author(s):  
Serdar Ünlü ◽  
Neçla Çakmak ◽  
Cevad Selam
Keyword(s):  
Decay Rates ◽  
Β Decay ◽  
Restoration Method

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

Beta-decay half-lives of the extremely neutron-rich nuclei in the closed-shell N = 50, 82, 126 groups

2021 ◽  
Author(s):  
Nguyen Kim Uyen ◽  
Kyung Yuk Chae ◽  
NgocDuy Nguyen ◽  
DuyLy Nguyen
Keyword(s):  
Half Life ◽  
Random Phase ◽  
Closed Shell ◽  
Decay Rates ◽  
Magic Numbers ◽  
Β Decay ◽  
R Process ◽  
Neutron Rich Isotopes ◽  
Semi Empirical ◽  
The Impact

Abstract The β--decay half-lives of extremely neutron-rich nuclei are important for understanding nucleosynthesis in the r-process. However, most of their half-lives are unknown or very uncertain, leading to the need for reliable calculations. In this study, we updated the coefficients in recent semi-empirical formulae using the newly updated mass (AME2020) and half-life (NUBASE2020) databases to improve the accuracy of the half-life prediction. In particular, we developed a new empirical model for better calculations of the β--decay half-lives of isotopes ranging in Z = 10 – 80 and N = 15-130. We examined the β--decay half-lives of the extremely neutron-rich isotopes at and around the neutron magic numbers of N = 50, 82, and 126 using either five different semi-empirical models or finite-range droplet model and quasi-particle random phase approximation (FRDM+QRPA) method. The β--decay rates derived from the estimated half-lives were used in calculations to evaluate the impact of the half-life uncertainties of the investigated nuclei on the abundance of the r-process. The results show that the half-lives mostly range in 0.001 < T1/2 < 100 s for the nuclei with a ratio of N/Z < 1.9; however, they differ significantly for those with the ratio of N/Z > 1.9. The half-life differences among the models were found to range from a few factors (for N/Z < 1.9 nuclei) to four orders of magnitude (for N/Z > 1.9). These discrepancies lead to a large uncertainty, which is up to four orders of magnitude, in the r-process abundance of isotopes. We also found that the multiple-reflection time-of-flight (MR-TOF) technique is preferable for precise mass measurements because its measuring timescale applies to the half-lives of the investigated nuclei. Finally, the results of this study are useful for studies on the β-decay of unstable isotopes and astrophysical simulations.

scholarly journals Two-phonon structures for beta-decay theory

2018 ◽  
Vol 194 ◽  
pp. 02008
Author(s):  
A.P. Severyukhin ◽  
N.N. Arsenyev ◽  
I.N. Borzov ◽  
R.G. Nazmitdinov ◽  
S. Åberg
Keyword(s):  
Random Matrix ◽  
Single Particle ◽  
Ground State ◽  
Matrix Theory ◽  
Decay Rates ◽  
Total Probability ◽  
Phonon Coupling ◽  
Skyrme Interaction ◽  
Β Decay ◽  
Gamow Teller

The β-decay rates of 60Ca have been studied within a microscopic model, which is based on the Skyrme interaction T45 to construct single-particle and phonon spaces. We observe a redistribution of the Gamow–Teller strength due to the phonon-phonon coupling, considered in the model. For 60Sc, the spin-parity of the ground state is found to be 1+. We predict that the half-life of 60Ca is 0.3 ms, while the total probability of the βxn emission is 6:1%. Additionally, the random matrix theory has been applied to analyze the statistical properties of the 1+ spectrum populated in the β-decay to elucidate the obtained results.

scholarly journals Results from the Cuore Experiment †

Universe ◽  
2019 ◽  
Vol 5 (1) ◽  
pp. 10 ◽  
Author(s):  
Alessio Caminata ◽  
Douglas Adams ◽  
Chris Alduino ◽  
Krystal Alfonso ◽  
Frank Avignone ◽  
...  
Keyword(s):  
Beta Decay ◽  
Energy Resolution ◽  
Half Life ◽  
Precise Measurement ◽  
Region Of Interest ◽  
Neutrinoless Double Beta Decay ◽  
Double Beta Decay ◽  
Effective Energy ◽  
Β Decay ◽  
Compact Structure

The Cryogenic Underground Observatory for Rare Events (CUORE) is the first bolometric experiment searching for neutrinoless double beta decay that has been able to reach the 1-ton scale. The detector consists of an array of 988 TeO 2 crystals arranged in a cylindrical compact structure of 19 towers, each of them made of 52 crystals. The construction of the experiment was completed in August 2016 and the data taking started in spring 2017 after a period of commissioning and tests. In this work we present the neutrinoless double beta decay results of CUORE from examining a total TeO 2 exposure of 86.3 kg yr , characterized by an effective energy resolution of 7.7 keV FWHM and a background in the region of interest of 0.014 counts / ( keV kg yr ) . In this physics run, CUORE placed a lower limit on the decay half-life of neutrinoless double beta decay of 130 Te > 1.3 · 10 25 yr (90% C.L.). Moreover, an analysis of the background of the experiment is presented as well as the measurement of the 130 Te 2 ν β β decay with a resulting half-life of T 1 / 2 2 ν = [ 7.9 ± 0.1 ( stat . ) ± 0.2 ( syst . ) ] × 10 20 yr which is the most precise measurement of the half-life and compatible with previous results.

scholarly journals Discrepancy between experimental and theoretical β-decay rates resolved from first principles

2019 ◽  
Vol 15 (5) ◽  
pp. 428-431 ◽  
Author(s):  
P. Gysbers ◽  
G. Hagen ◽  
J. D. Holt ◽  
G. R. Jansen ◽  
T. D. Morris ◽  
...  
Keyword(s):  
First Principles ◽  
Decay Rates ◽  
Β Decay

Effects of Antineutrino mass on β−-Decay Rates Calculated Within the Gross Theory of Beta Decay

2019 ◽  
Vol 50 (1) ◽  
pp. 57-63 ◽  
Author(s):  
M. R. Azevedo ◽  
R. C. Ferreira ◽  
A. J. Dimarco ◽  
C. A. Barbero ◽  
A. R. Samana ◽  
...  
Keyword(s):  
Beta Decay ◽  
Decay Rates ◽  
Β Decay
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