Galactic cosmic-ray propagation in the light of AMS-02: I. Analysis of protons, helium, and antiprotons

Abstract

We present novel constraints on cosmic-ray propagation in the Galaxy using the recent precise measurements of proton and helium spectra from AMS-02, together with preliminary AMS-02 data on the antiproton over proton ratio. To explore efficiently the large (up to eleven-dimensional) parameter space we employ the nested-sampling algorithm as implemented in the \textsc{MultiNest} package, interfaced with the \textsc{Galprop} code to compute the model-predicted spectra. We use VOYAGER proton and helium data, sampling the local inter-stellar spectra, to constrain the solar modulation potential. We find that the turbulence of the Galactic magnetic field is well constrained, i.e., $\delta =0.30_{-0.02}^{+0.03}(stat{)}_{-0.04}^{+0.10}(sys)$, with uncertainties dominated by systematic effects. Systematic uncertainties are determined checking the robustness of the results to the minimum rigidity cut used to fit the data (from 1 GV to 5 GV), to the propagation scenario (convection vs no-convection), and to the uncertainties in the knowledge of the antiproton production cross section. Convection and reaccelaration are found to be degenerate and not well-constrained singularly when using data above 5 GV. Using data above 1 GV reacceleration is required, $v_{\mathrm{A}}=25\pm 2$km/s, although this value might be significantly affected by the low energy systematic uncertainty in the solar modulation. In a forthcoming companion paper, we investigate the constraints imposed by AMS-02 measurements on lithium, boron, and carbon.

20 pages, 15 figures, 4 tables; V3: Updated to the final PRD version

References in corpus (6)

• Observation of an anomalous positron abundance in the cosmic radiation
• Cosmic-Ray Proton and Helium Spectra from the First CREAM Flight
• Spectral breaks as a signature of cosmic ray induced turbulence in the Galaxy
• Inhomogeneity in the Supernova Remnant Distribution as the Origin of the PAMELA Anomaly
• The Cosmic Ray Antiproton Background for AMS-02
• A Markov Chain Monte Carlo for Galactic Cosmic Ray physics: I. Method and results for the Leaky Box Model

Cited by in corpus (6)

• Scrutinizing the evidence for dark matter in cosmic-ray antiprotons
• Cosmic-ray transport from AMS-02 B/C data: benchmark models and interpretation
• Handling the Uncertainties in the Galactic Dark Matter Distribution for Particle Dark Matter Searches
• Power requirements for cosmic ray propagation models involving diffusive reacceleration; estimates and implications for the damping of interstellar turbulence
• Cosmic-ray antiprotons in the AMS-02 era: A sensitive probe of dark matter
• Hadronic Interactions of Energetic Charged Particles in Protogalactic Outflow Environments and Implications for the Early Evolution of Galaxies