2018/02/12 by M. R. Mumpower, T. Kawano, T. M. Sprouse +4 · 1 citation
Physics and Astronomy · #nucl-th #astro-ph.SR
paper · pdf · doi:10.3847/1538-4357/aaeaca
9 pages, 5 figures, submitted
arxiv created 2018/02/12 · arxiv updated 2018/12/12
We present β-delayed neutron emission and β-delayed fission calculations for heavy, neutron-rich nuclei using the coupled Quasi-Particle Random Phase Approximation plus Hauser-Feshbach (QRPA+HF) approach. From the initial population of a compound nucleus after β-decay, we follow the statistical decay taking into account competition between neutrons, γ-rays, and fission. We find a region of the chart of nuclides where the probability of β-delayed fission is ∼100%, that likely prevents the production of superheavy elements in nature. For a subset of nuclei near the neutron dripline, neutron multiplicity and the probability of fission are both large, leading to the intriguing possibility of multi-chance β-delayed fission, a new decay mode for extremely neutron-rich heavy nuclei. In this new decay mode, β-decay can be followed by multiple neutron emission leading to subsequent daughter generations which each have a probability to fission. We explore the impact of β-delayed fission in rapid neutron capture process (r-process) nucleosynthesis in the tidal ejecta of a neutron star--neutron star merger and show that it is a key fission channel that shapes the final abundances near the second r-process peak.