Speaker
Description
Nucleosynthesis above the iron region mainly proceeds via successive neutron capture processes, such as the s- and r-processes. However, in the case of neutrino-driven ejecta from a core-collapse supernova, nucleosynthesis runs relatively close to the valley of stability, hence it proceeds mainly via (α,n) and (p,n) reactions towards higher mass numbers [1]. Sensitivity studies have shown that (α,n) reaction uncertainties can be up to an order of magnitude, mainly due to differences in α-nucleus optical model (αOM) potentials [2]. This nuclear uncertainty significantly impacts network calculations and calculated abundances [3,4].
Therefore, substantial effort has been devoted to measuring key (α,n) reactions that influence the weak r-process, such as the $^{86}$Kr(α,n)$^{89}$Sr reaction. These measurements have also been used to justify the adoption of a new αOMP, ATOMKI-V2 [5]. However, our latest reaction network study suggests that the impact of (p,n) reaction uncertainties should not be so easily disregarded as has been done so far. During our measurement campaigns, we measured the cross sections in the Gamow window for both $^{86}$Kr(α,n) and $^{86}$Kr(p,n) reactions [6,7]. In this presentation, we will share details on our experimental results, the application of ATOMKI-V2, the significance of (p,n) reactions, and the astrophysical implications of our new data.
[1] A. Arcones and F. Montes, ApJ, 731 5 (2011).
[2] J. Pereira and F. Montes, Phys. Rev. C, 93 034611 (2016)
[3] J. Bliss, A. Arcones, F. Montes, and J. Pereira, Phys. Rev. C, 101 055807 (2020)
[4] A. Psaltis et al., ApJ, 935 27 (2022)
[5] P. Mohr et al., Eur. Phys. J. A, 61 89 (2025)
[6] G. G. Kiss et al., ApJ, 988 170 (2025)
[7] S. R. Kovács, in preparation