2019/04/25 by Yoann Genolini, Mathieu Boudaud, Pedro Ivo Batista +11
Physics and Astronomy · #astro-ph.HE #hep-ph
paper · pdf · doi:10.1103/physrevd.99.123028
published as Phys. Rev. D 99, 123028 (2019) · 16 pages, 4 figures: typo on a parameter fixed (Tables and Fig.3 updated), conclusions unchanged
arxiv created 2019/04/25 · arxiv updated 2019/07/03
This article aims at establishing 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 (\gtrsim10GV), i.e. independent of the propagation scenario: at 1σ, the diffusion slope δ is [0.43-0.53], whereas K10, the diffusion coefficient at 10GV, is [0.26-0.36]kpc2Myr-1; we confirm the robustness of the high-energy break, with a typical value Δh∼ 0.2. We also find a hint for a similar (reversed) feature at low rigidity around the B/C peak (∼ 4GV) which might be related to some effective damping scale in the magnetic turbulence.