http://arxiv.org/abs/2203.00522
Li, Be, and B high-precision data from AMS-02 provide the best constraints on Galactic cosmic-ray transport parameters. We re-evaluate the impact of Fe fragmentation on the Li, Be, and B modelling. We discuss the consequences on the transport parameter determination and reassess whether a primary source of Li is needed to match AMS-02 data. We renormalise several cross-section parametrisations to existing data for the most important reactions producing Li, Be, and B. We use the \usine{} code with these new cross-section sets to re-analyse Li/C, Be/C, and B/C AMS-02 data. We build three equally plausible cross-section sets. Compared to the use of the initial cross-section sets, they lead to an average enhanced production of Li ($\sim20-50\%$) and Be ($\sim5-15\%$), while leaving the B flux mostly unchanged. In particular, Fe fragmentation is found to contribute to up to 10\% of the Li and Be fluxes. Used in the combined analysis of AMS-02 Li/C, Be/C, and B/C data, the fit is significantly improved, with an enhanced diffusion coefficient ($\sim 20\%)$. The three updated cross-section sets are found to either slightly undershoot or overshoot the Li/C and B/C ratios: this strongly disfavours evidences for a primary source of Li in cosmic rays. We stress that isotopic cosmic-ray ratios of Li (and to a lesser extent Be), soon to be released by AMS-02, are also impacted by the use of these updated sets. Almost no nuclear data exist for the production of Li and B isotopes from Ne, Mg, Si, and Fe, whereas these reactions are estimated to account for $\sim 20\%$ of the total production. Some new nuclear measurements are clearly desired to better exploit the high-precision AMS-02 cosmic-ray data.
D. Maurin, E. Bueno, Y. Génolini, et. al.
Wed, 2 Mar 22
25/54
Comments: 20 pages, 16 figures, 2 tables (submitted to A&A)