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

Abstract

We investigated the effects of first-forbidden transitions in β decays on the production of the r-process Ã. 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 Ñ. 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.