Dark Matter Search in Space: Combined Analysis of Cosmic Ray
  Antiproton-to-Proton Flux Ratio and Positron Flux Measured by AMS-02
  Dark matter search in space has been carried out for many years. Measurements
of cosmic ray photons, charged antiparticles and neutrinos are useful tools for
dark matter indirect search. The antiparticle energy spectra of cosmic rays
have several exciting features such as the unexpected positron excess at energy
about 10 -- 500 GeV and the remarkably flattening antiproton/proton at energy
about 60--450 GeV precisely measured by the AMS-02 experiment, which can not be
explained simultaneously by secondary production in interstellar medium. In
this work, we report a combined analysis of cosmic ray antiproton and positron
spectra arising from dark matter on the top of a secondary production in a
spatial-dependent propagation model. We discuss the systematics from antiproton
production cross section using the two latest Monte Carlo generators, i.e. EPOS
LHC and QGSJET-II-04m, respectively. We compare their results. In the case of
EPOS LHC, we find that the dark matter pair annihilating into tau leptons
channel with 100% branching ratio is the only possible one channel scenario to
explain data. On the other hand, there is not a single possible channel in the
case of QGSJET-II-04m. We also propose possible two-channel scenarios based on
these two Monte Carlo generators.
