Impact of the first-forbidden β decay on the production of A∼195 r-process peak

Physics Letters B

Nobuya Nishimura¹  Dong-Liang Fang²  Toshio Suzuki³  Zsolt Podolyák⁴ 

[1]Astrophysics Group, Keele University, Keele ST5 5BG, UK

[2]College of Physics, Jilin University, Changchun, Jilin 130012, China

[3]Department of Physics, Nihon University, Sakurajosui, Tokyo 156-8550, Japan

[4]Department of Physics, University of Surrey, Guildford GU2 7XH, UK

关键词: r-Process;    Solar abundances;    β-Decay;    First-forbidden transition;    Neutron emission;    QRPA;   

DOI  :  10.1016/j.physletb.2016.03.025

来源: DOAJ

【 摘 要 】

We investigated the effects of first-forbidden transitions in β decays on the production of the r-process A∼195 peak. The theoretical calculated β-decay rates with β-delayed neutron emission were examined using several astrophysical conditions. As the FF decay is dominant in N∼126 neutron-rich nuclei, their inclusion shortens β-decay lifetimes and shifts the abundance peak towards higher masses. Additionally, the inclusion of the β-delayed neutron emission results in a wider abundance peak, and smoothens the mass distribution by removing the odd–even mass staggering. The effects are commonly seen in the results of all adopted astrophysical models. Nevertheless there are quantitative differences, indicating that remaining uncertainty in the determination of half-lives for N=126 nuclei is still significant in order to determine the production of the r-process peak.

【 授权许可】

Unknown