The role of fission in mass sensitivity study of the <i>r</i> -process*

Abstract A sensitivity study was performed to investigate the impact of individual nuclear masses on r -process rare-earth peak abundances in different astrophysical scenarios. The most impactful nuclei are primarily distributed in two regions on the nuclear chart: one located 20-30 neutrons away from stability (defined as region I) and another 7-15 neutrons away from stability (defined as region II), as previously reported in Phys. Lett. B 844, 138092 (2023). In this study, we extend our analysis by focusing on the role of fission in the mass sensitivity study. The results show that, in astrophysical scenarios involving fission, the sensitivity of nuclei in region I is diminished owing to the deposition of a large number of fission fragments in the rare-earth mass region. However, nuclei in region II retain high sensitivity because the contribution of fission decreases in the later stages of nucleosynthesis. This study highlights the impact of fission on the sensitivity of r -process abundances to nuclear masses and enhances the understanding of the rare-earth peak formation mechanism.