Collective effects induced by charge-exchange vibrational modes on 0− → 0+ and 2− → 0+ first-forbidden β-decay transitions

doi:10.1016/0375-9474(86)90028-X

Nuclear Physics A

Volume 453, Issue 1, 12 May 1986, Pages 45-57

https://doi.org/10.1016/0375-9474(86)90028-X Get rights and content

Abstract

The influence of collective effects associated with spin-isospin-dependent modes upon unique first-forbidden β-decay transitions is studied. The ft values for the 0⁻ → 0⁺ and 2⁻ → 0⁺ transitions, in the mass region 70 ≤ A ≤ 214, are calculated and compared with the experimental data.

References (33)

F. Krmpotić et al.
Nucl. Phys.
(1980)
F. Krmpotić
Nucl. Phys.
(1981)
F. Krmpotić et al.
Nucl. Phys.
(1983)
J. Krumlinde et al.
Nucl. Phys.
(1984)
D.J. Horen
Phys. Lett.
(1980)
D.J. Horen
Phys. Lett.
(1981)
C. Gaarde
Nucl. Phys.
(1981)
H. Ejiri
Nucl. Phys.
(1972)
K. Nakayama et al.
Phys. Lett.
(1982)
G.E. Brown et al.
Nucl. Phys.
(1981)

M. Rho

Nucl. Phys.

(1974)

S.G. Nilsson

Nucl. Phys.

(1969)

J. Damgaard et al.

Nucl. Phys.

(1969)

P.A.M. Guichon et al.

Phys. Lett

(1979)

P.A.M. Guichon et al.

Nucl. Phys.

(1982)

H.U. Jager et al.

Nucl. Phys.

(1983)

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Unique first-forbidden β-decay transitions in odd–odd and even–even heavy nuclei
2017, Nuclear Physics A
The allowed Gamow–Teller (GT) transitions are the most common weak nuclear processes of spin–isospin $(σ τ)$ type. These transitions play a key role in numerous processes in the domain of nuclear physics. Equally important is their contribution in astrophysics, particularly in nuclear synthesis and supernova-explosions. In situations where allowed GT transitions are not favored, first-forbidden transitions become significant, specifically in medium heavy and heavy nuclei. For neutron-rich nuclei, first-forbidden transitions are favored mainly due to the phase-space amplification for these transitions. In this work we calculate the allowed GT as well as unique first-forbidden (U1F) $| Δ J | = 2$ transitions strength in odd–odd and even–even nuclei in mass range $70 \leq A \leq 214$ . Two different pn-QRPA models were used with a schematic separable interaction to calculate GT and U1F transitions. The inclusion of U1F strength improved the overall comparison of calculated terrestrial β-decay half-lives in both models. The ft values and reduced transition probabilities for the $2^{-} ⟷ 0^{+}$ transitions were also calculated. We compared our calculations with the previously reported correlated RPA calculation and experimental results. Our calculations are in better agreement with measured data. For stellar applications we further calculated the allowed GT and U1F weak rates. These include $β^{\pm}$ -decay rates and electron/positron capture rates of heavy nuclei in stellar matter. Our study shows that positron and electron capture rates command the total weak rates of these heavy nuclei at high stellar temperatures.
Nuclear Data Sheets for A = 84
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The evaluated spectroscopic data are presented for 12 known nuclides of mass 84 (Ga, Ge, As, Se, Br, Kr, Rb, Sr, Y, Zr, Nb, Mo). Except for the stable nuclides ⁸⁴Sr and ⁸⁴Kr, extensive new data are available for all the other nuclides since the 1997 evaluation by J.K. Tuli (1997Tu02) of A = 84 nuclides. Many precise Penning-trap mass measurements since AME-2003 for A = 84 nuclides (2009Re03,2008Ha23,2008We10,2007Ke09,2006Ka48,2006De36,2006Ri15) have resulted in improved Q values and separation energies. However, many deficiencies still remain. Some examples are given below. Excited-state data for ⁸⁴Ga and ⁸⁴As are nonexistent, and those for ⁸⁴Ge are scarce. The radioactive decay schemes of ⁸⁴Ga, ⁸⁴Ge, ⁸⁴Se, ⁸⁴Y (39.5 min), ⁸⁴Y (4.6 s), ⁸⁴Zr and ⁸⁴Nb suffer from incompleteness and that for ⁸⁴Mo decay is not known at all. The energy ordering of the two activities (39.5 min and and 4.6 s) of ⁸⁴Y is not well established, although, high-spin with tentative spin-parity of (6+) is adopted here as the ground state of ⁸⁴Y based on weak arguments. From a conference report published in 2000, it is clear that extensive experiments were done to investigate decays of ⁸⁴Zr and ⁸⁴Y, but details of these studies never appeared in literature and none were made available to the evaluators when requested from original authors.
This evaluation was carried out as part of ENSDF workshop for Nuclear Structure and Decay Data Evaluators, organized and hosted by the “Horia Hulubei” National Institute for Physics and Nuclear Engineering, Bucharest, Romania during March 30, 2009 – April 3, 2009. Names of the evaluators principally responsible for evaluation of individual nuclides are given under the respective Adopted data sets.
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Nuclear data sheets for A = 86
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Contributions of unique first-forbidden transitions to two-neutrino double-β-decay half-lives
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The two-neutrino double-β-decay transition of ⁷⁶Ge to the ground state of ⁷⁶Se is calculated using a realistic proton-neutron force and including unique first-forbidden single-β-decay transitions to virtual 2⁻ intermediate states. The corresponding nuclear matrix elements are computed by using the proton-neutron quasiparticle random-phase approximation (pn-QRPA). From the results of the present study it is concluded that the inclusion of virtual unique first-forbidden transitions, as possible “new” steps contributing to the half-life of the two-neutrino double-β-decay mode, can be disregarded.
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^a: Fellow of the CONICET, Argentina.

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Collective effects induced by charge-exchange vibrational modes on 0− → 0+ and 2− → 0+ first-forbidden β-decay transitions

Abstract

Nucl. Phys.

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Collective effects induced by charge-exchange vibrational modes on 0⁻ → 0⁺ and 2⁻ → 0⁺ first-forbidden β-decay transitions