# Some new hints on cosmic-ray propagation from AMS-02 nuclei spectra

## TL;DR

This study analyzes AMS-02 nuclei spectra to identify key features of cosmic-ray propagation, favoring a high-rigidity break in diffusion coefficient and suggesting the presence of slow diffusion zones and additional secondary CR injection.

## Contribution

It provides new insights into cosmic-ray propagation by favoring a diffusion coefficient break over a primary source break and highlights the need for considering slow diffusion zones and extra secondary injection.

## Key findings

- High-rigidity break at ~325 GV in diffusion coefficient is favored.
- Secondary fluxes are underestimated by current models.
- Evidence suggests the existence of slow diffusion zones.

## Abstract

In this work, we considered 2 schemes (a high-rigidity break in primary source injections and a high-rigidity break in diffusion coefficient) to reproduce the newly released AMS-02 nuclei spectra (He, C, N, O, Li, Be, and B) when the rigidity larger than 50 GV. The fitting results show that current data set favors a high-rigidity break at $\sim 325 \mathrm{GV}$ in diffusion coefficient rather than a break at $\sim 365 \mathrm{GV}$ in primary source injections. Meanwhile, the fitted values of the factors to rescale the cosmic-ray (CR) flux of secondary species/components after propagation show us that the secondary flux are underestimated in current propagation model. It implies that we might locate in a slow diffusion zone, in which the CRs propagate with a small value of diffusion coefficient compared with the averaged value in the galaxy. Another hint from the fitting results show that extra secondary CR nuclei injection may be needed in current data set. All these new hints should be paid more attention in future research.