Abstract
Background: The astrophysical -process occurs in an explosive astrophysical event under extremely neutron-rich conditions, leading to equilibrium along isotopic chains which peaks around neutron separation energies of a few MeV. Nuclei with larger are usually produced by decay, but under certain conditions also -induced reactions may become relevant for the production of nuclei with .
Purpose: The uncertainties of the reaction rates of these -induced reactions are discussed within the statistical model. As an example, -induced and reaction cross sections for the neutron-rich nucleus are studied in detail.
Method: In a first step, the relevance of and reactions is analyzed. Next the uncertainties are determined from a variation of the -nucleus potential which is the all-dominant parameter for the astrophysical reaction rate.
Results: It is found that the -process flow towards nuclei with larger is essentially influenced only by the -nucleus potential whereas the other ingredients of the statistical model play a very minor role. This finding is based on the fact that the flow towards larger depends on the sum over all cross sections, which is practically identical to the total -induced reaction cross section.
Conclusions: -nucleus potentials play an important role under certain -process conditions because the flow towards larger depends sensitively on the total -induced reaction cross section. The uncertainty of the reaction rate is about a factor of two to three at higher temperatures and exceeds one order of magnitude at very low temperatures.
- Received 15 April 2016
DOI:https://doi.org/10.1103/PhysRevC.94.035801
©2016 American Physical Society