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Cosmic-ray transport from AMS-02 B/C data: Benchmark models and interpretation

par Genolini, Yoann ;Boudaud, Mathieu;Batista, P.I.;Caroff, Sami;Derome, Laurent;Lavalle, Julien;Marcowith, Alexandre;Maurin, David;Poireau, Vincent;Poulin, Vivian;Rosier, Sylvie;Salati, Pierre;Serpico, Pasquale Dario;Vecchi, Manuela
Référence Pos proceedings of science, 358
Publication Publié, 2019

Article révisé par les pairs

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Résumé :

We present new benchmark scenarios for Galactic cosmic-ray propagation in the GV-TV rigidity range, based on fits to the AMS-02 B/C data with the USINE V3.5 propagation code. We employ a new fitting procedure, cautiously taking into account data systematic error correlations in different rigidity bins and considering Solar modulation potential and leading nuclear cross section as nuisance parameters. We delineate specific low, intermediate, and high-rigidity ranges that can be related to both features in the data and peculiar microphysics mechanisms resulting in spectral breaks. We single out a scenario which yields excellent fits to the data and includes all the presumably relevant complexity, the BIG model. This model has two limiting regimes: (i) the SLIM model, a minimal diffusion-only setup, and (ii) the QUAINT model, a convection-reacceleration model where transport is tuned by non-relativistic effects. All models lead to robust predictions in the high-energy regime (& 10 GV), i.e. independent of the propagation scenario: at 1s, the diffusion slope d is [0.43 - 0.53], whereas K10, the diffusion coefficient at 10 GV, is [0.26 - 0.36] kpc2 Myr-1; we confirm the robustness of the high-energy break, with a typical value ?h ~ 0.2. We also find a hint for a similar (reversed) feature at low rigidity around the B/C peak (~ 4 GV) which might be related to some effective damping scale in the magnetic turbulence. Initialization files used for the analysis, along with the resulting best-fit values and covariance matrix of best-fit parameters are provided with USINE V3.5.