Implications of Li to O data of AMS-02 on our understanding cosmic-ray propagation

Discussion timeslot (ZOOM-Meeting): 19. July 2021 - 18:00
ZOOM-Meeting URL: https://desy.zoom.us/j/91896950007
ZOOM-Meeting ID: 91896950007
ZOOM-Meeting Passcode: ICRC2021
Corresponding Session: https://icrc2021-venue.desy.de/channel/18-Cosmic-Ray-Secondary-nuclei-observations-and-impact-on-theories-CRD/71
Live-Stream URL: https://icrc2021-venue.desy.de/livestream/Discussion-06/7

Abstract:
In the last decade, the space-borne experiment AMS-02 has determined cosmic-ray spectra with unprecedented precision, potentially providing new insights into cosmic-ray propagation in our Galaxy. However, the analysis of this increasingly precise cosmic-ray data requires more careful modeling of systematic uncertainties.rnI will review the conclusions from the analysis of the secondary cosmic rays of Li, Be, and B, and the primaries C, N, and O. To investigate the uncertainties in the propagation scenarios, we have considered five different propagation frameworks, including detailed analyses of the break in cosmic-ray diffusion coefficient at a rigidity of a few GV and models of Alfvenic reacceleration. Global fits of these propagation frameworks have been performed utilizing the GALPROP code to solve the diffusion equations of cosmic rays. Systematic uncertainties arising from the nuclear production cross sections of secondaries have been taken into account as nuisance parameters. Furthermore, the impact of correlations in the systematic uncertainties of the AMS-02 data is studied.rnWe find that, in particular, the uncertainties on the nuclear production cross sections prevent a deeper understanding of the properties of CR propagation. Nonetheless, we find robust constraints on the slope of the diffusion coefficient at intermediate rigidities of $\delta\simeq0.4-0.5$ and a lower bound on the half-height of the diffusion halo at $z_\mathrm{h} larger 3\,\mathrm{kpc}$. In all considered propagation scenarios, the fits are compatible with zero convection.'

Authors: Michael Korsmeier
Co-Authors: Alessandro Cuoco
Indico-ID: 1307
Proceeding URL: https://pos.sissa.it/395/176