Unique first-forbidden ?-decay transitions in odd-odd and even-even heavy nuclei
Küçük Resim Yok
Tarih
2017
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Elsevier Science Bv
Erişim Hakkı
info:eu-repo/semantics/closedAccess
Özet
The allowed Gamow Teller (GT) transitions are the most common weak nuclear processes of spin-isospin (sigma tau) 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) vertical bar Delta J vertical bar = 2 transitions strength in odd odd and even-even nuclei in mass range 70 <= A <= 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 beta-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 beta(+/-)-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. (C) 2016 Elsevier B.V. All rights reserved.
Açıklama
Anahtar Kelimeler
Gamow-Teller transitions, Unique first-forbidden transitions, pn-QRPA theory, Heavy nuclei, beta(+/-)-decay rates, Electron/positron capture rates
Kaynak
Nuclear Physics A
WoS Q Değeri
Q2
Scopus Q Değeri
Q2
Cilt
957
