Abstract
The direct and semi-direct (DSD) components of the neutron capture cross sections are calculated for a series of tin isotopes by employing a single-particle potential (SPP) that gives a good reproduction of the known single-particle energies (SPEs) over a wide mass region. The results are compared with the Hauser-Feshbach (HF) contribution in the energy region of astrophysical interest. The calculated result shows that the HF component drops off rapidly for isotope $^{132}\mathrm{Sn}$ and toward more neutron-rich ones, whereas the DSD component decreases only smoothly and eventually becomes dominant. This result is consistent with those of previous studies, but the dependence of the DSD cross section on the target mass number is a feature of the present SPP that gives a smooth variation of SPEs. As a consequence, the direct portion of the DSD component gives the largest contribution to the total ($n,\ensuremath{\gamma}$) cross section for neutron-rich isotopes below a few MeV. Therefore, the direct capture process modifies the astrophysical ($n,\ensuremath{\gamma}$) reaction rates to a great extent. The semi-direct component, however, gives a negligible contribution to the astrophysical reaction rates, but its impact is significant above several MeV. The reason for the difference in isotopic dependence between the HF and DSD components is discussed, and its implication for $r$-process nucleosynthesis is given.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.