# The International Cosmic Ray Conference 2017

12-20 July 2017
BEXCO
Asia/Seoul timezone
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# Contribution

BEXCO - Room F(201/202/203/204)

# [CRD068] Cosmic ray propagation after AMS-02

• Qiang YUAN

## Co-authors

• Xiao-Jun BI (Institute of High Energy Physics, CAS)
• Kun FANG (Institute of High Energy Physics, CAS)
• Su-Jie LIN (Institute of High Energy Physics, CAS)

## Description

The precise measurements of cosmic ray fluxes and ratios by AMS-02 enable significantly improved constraints on the propagation models of cosmic rays. Here we use the newly reported Boron-to-Carbon ratio (B/C) from AMS-02 and the time-dependent proton fluxes from PAMELA and AMS-02 to constrain the source and propagation parameters of cosmic rays in the Milky Way. A comprehensive set of propagation models, with/without reacceleration or convection, have been discussed and compared. We find that only the models with reacceleration can self-consistently fit both the proton and B/C data. The rigidity dependence slope of the diffusion coefficient, $delta$, is found to be about $0.38-0.50$ for the diffusion-reacceleration models. The plain diffusion and diffusion-convection models fit the data poorly. We compare different model predictions of the positron and antiproton fluxes with the data. We find that the diffusion-reacceleration models over-produce low energy positrons, while non-reacceleration models give better fit to the data. As for antiprotons, reacceleration models tend to under-predict low energy antiproton fluxes, unless a phenomenological modification of the velocity-dependence of the diffusion coefficient is applied. Our results suggest that there could be important differences of the propagation for nuclei and leptons, in either the Milky Way or the solar heliosphere.