Antiproton Flux, Antiproton-to-Proton Flux Ratio, and Properties of Elementary Particle Fluxes in Primary Cosmic Rays Measured with the Alpha Magnetic Spectrometer on the International Space Station
A precision measurement by AMS of the antiproton flux and the antiproton-to-proton flux ratio in primary cosmic rays in the absolute rigidity range from 1 to 450 GV is presented based on $3.49 \times 10^5$ antiproton events and $2.42 \times 10^9$ proton events. The fluxes and flux ratios of charged elementary particles in cosmic rays are also presented. In the absolute rigidity range ~60 to ~500 GV, the antiproton $ \bar{p} $,proton $p$ , and positron $e^{+}$ fluxes are found to have nearly identical rigidity dependence and the electron $e^-$ flux exhibits a different rigidity dependence. Below 60 GV, the ($\bar{p}/p$), ($\bar{p}/e^-$), and ($p/e^{+}$) flux ratios each reaches a maximum. From ~60 to ~500 GV, the ($\bar{p}/p $), ($\bar{p}/e^+ $), and ($\bar{p}/e^+ $) flux ratios show no rigidity dependence. These are new observations of the properties of elementary particles in the cosmos.
The CRDB at LPSC/IN2P3/CNRS, online since 2013, is fully described in Maurin et al. (2014, 2020)
The CRDB © SSDC is developed at the Space Science Data Center, a facility of the Italian Space Agency (ASI).