βdelayed Fission in rprocess Nucleosynthesis
Abstract
We present βdelayed neutron emission and βdelayed fission (βdf) calculations for heavy, neutronrich nuclei using the coupled QuasiParticle Random Phase Approximation plus HauserFeshbach (QRPA+HF) approach. From the initial population of a compound nucleus after βdecay, we follow the statistical decay, taking into account competition between neutrons, γrays, and fission. We find a region of the chart of nuclides where the probability of βdf is ∼100%, which 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 multichance βdf, a decay mode for extremely neutronrich heavy nuclei. In this decay mode, βdecay can be followed by multiple neutron emission, leading to subsequent daughter generations that each have a probability to fission. We explore the impact of βdf in rapid neutroncapture process (rprocess) nucleosynthesis in the tidal ejecta of a neutron starneutron star merger and show that it is a key fission channel that shapes the final abundances near the second rprocess peak.
 Publication:

The Astrophysical Journal
 Pub Date:
 December 2018
 DOI:
 10.3847/15384357/aaeaca
 arXiv:
 arXiv:1802.04398
 Bibcode:
 2018ApJ...869...14M
 Keywords:

 binaries: close;
 gravitational waves;
 nuclear reactions;
 nucleosynthesis;
 abundances;
 Nuclear Theory;
 Astrophysics  Solar and Stellar Astrophysics
 EPrint:
 9 pages, 5 figures, submitted