The \(^{59}\)Fe(n, {\gamma})\(^{60}\)Fe Cross Section from the Surrogate Ratio Method and Its Effect on the \(^{60}\)Fe Nucleosynthesis

• Published in: arXiv.org 2021-09
• Main Authors: Yan, S Q, Li, X Y, Nishio, K, Lugaro, M, Li, Z H, Makii, H, Pignatari, M, Wang, Y B, Orlandi, R, Hirose, K, Tsukada, K, Mohr, P, Li, G S, Wang, J G, Gao, B S, Han, Y L, Guo, B, Li, Y J, Shen, Y P, Sato, T K, Ito, Y, Suzaki, F, J Su, Yang, Y Y, Wang, J S, Ma, J B, P Ma, Bai, Z, Xu, S W, Ren, J, Fan, Q W, Zeng, S, Han, Z Y, Nan, W, Nan, W K, Chen, C, Lian, G, Q Hu, Duan, F F, Jin, S Y, Tang, X D, Liu, W P
• Format: Article
• Language: English
• Subjects: Constraints; Cross-sections; Gamma rays; Half-life; Impact analysis; Massive stars; Milky Way; Nuclear capture; Nuclear fusion; Stellar physics; Supernovae; Uncertainty
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.2109.12654

The long-lived \(^{60}\)Fe (with a half-life of 2.62 Myr) is a crucial diagnostic of active nucleosynthesis in the Milky Way galaxy and in supernovae near the solar system. The neutron-capture reaction \(^{59}\)Fe(n,\(\gamma\))\(^{60}\)Fe on \(^{59}\)Fe (half-life = 44.5 days) is the key reaction for the production of \(^{60}\)Fe in massive stars. This reaction cross section has been previously constrained by the Coulomb dissociation experiment, which offered partial constraint on the \(E\)1 \(\gamma\)-ray strength function but a negligible constraint on the \(M\)1 and \(E\)2 components. In this work, for the first time, we use the surrogate ratio method to experimentally determine the \(^{59}\)Fe(n,\(\gamma\))\(^{60}\)Fe cross sections in which all the components are included. We derived a Maxwellian-averaged cross section of 27.5 \(\pm\) 3.5 mb at \(kT\)= 30 keV and 13.4 \(\pm\) 1.7 mb at \(kT\)= 90 keV, roughly 10 - 20% higher than previous estimates. We analyzed the impact of our new reaction rates in nucleosynthesis models of massive stars and found that uncertainties in the production of \(^{60}\)Fe from the \(^{59}\)Fe(n,\(\gamma\))\(^{60}\)Fe rate are at most of 25%. We conclude that stellar physics uncertainties now play a major role in the accurate evaluation of the stellar production of \(^{60}\)Fe.