β
-decay rates of 
Rh115,117
 into 
Pd115,117
 isotopes in the microscopic interacting boson-fermion model

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.

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Two-phonon structures for beta-decay theory

EPJ Web of Conferences ◽

10.1051/epjconf/201819402008 ◽

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.

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STUDY OF β DECAY IN THE As-Ge ISOTOPES IN THE INTERACTING BOSON-FERMION MODEL

Key Topics in Nuclear Structure ◽

10.1142/9789812702265_0040 ◽

2005 ◽

Author(s):

N. YOSHIDA ◽

L. ZUFFI ◽

S. BRANT

Keyword(s):

Β Decay ◽

Fermion Model

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

Nature Physics ◽

10.1038/s41567-019-0450-7 ◽

2019 ◽

Vol 15 (5) ◽

pp. 428-431 ◽

Cited By ~ 59

Author(s):

P. Gysbers ◽

G. Hagen ◽

J. D. Holt ◽

G. R. Jansen ◽

T. D. Morris ◽

...

Keyword(s):

First Principles ◽

Decay Rates ◽

Β Decay

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

Brazilian Journal of Physics ◽

10.1007/s13538-019-00723-z ◽

2019 ◽

Vol 50 (1) ◽

pp. 57-63 ◽

Cited By ~ 1

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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The PANDORA project: an experimental setup for measuring in-plasma β-decays of astrophysical interest

EPJ Web of Conferences ◽

10.1051/epjconf/202022701013 ◽

2020 ◽

Vol 227 ◽

pp. 01013

Author(s):

David Mascali ◽

Maurizio Busso ◽

Alberto Mengoni ◽

Simone Amaducci ◽

Castro Giuseppe ◽

...

Keyword(s):

Nuclear Astrophysics ◽

Charge State Distribution ◽

Decay Rates ◽

Nuclear Decay ◽

Early Solar System ◽

State Distribution ◽

Β Decay ◽

Plasma Trap ◽

First Time ◽

Magnetic Plasma

Experiments performed on Storage Rings have shown that lifetimes of beta-radionuclides can change dramatically as a function of theionization state. PANDORA (Plasmas for Astrophysics, Nuclear Decay Observation and Radiation for Archaeometry) aims at measuring, for the first time, nuclear β-decay rates in stellar-like conditions, especially for radionuclides involved in nuclear-astrophysics processes (BBN, s- processing, CosmoChronometers, Early Solar System formation). Compact magnetic plasma traps, where plasmas reach density ne~10n-1014 cm-3, and temperature Te~0.1-30 keV, are suitable for such studies. The decay rates can be measured as a function of the charge state distribution of the inplasma ions. The collaboration is now designing the plasma trap able to reach the needed plasma densities, temperatures and charge states distributions. A first list of radioisotopes, including tens of physics cases of potential interest is now available. Possible physics cases include, among the others, 2°4Tl, 63Ni, 6°Co, 171Tm, 147Pm, 85Kr, 176Lu and the pairs 187Re-187Os and 87Sr-87Rb, which play a crucial role as cosmo-clock. Physics cases are now under evaluation in terms of lifetime measurements feasibility in a plasma trap.

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