摘要：We present a scenario where dark matter is in the form of dark
atoms that can accommodate the experimentally observed excess of
positrons in PAMELA and AMS-02 while being compatible with the
constraints imposed on the gamma-ray
ux from Fermi/LAT. This
scenario assumes that the dominant component of dark matter is in
the form of a bound state between a helium nucleus and a particle
and a small component is in the form of a WIMP-like dark atom
compatible with direct searches in underground detectors. One of
the constituents of this WIMP-like state is a metastable particle
with a mass of 1 TeV or slightly below that by decaying to ,
and produces the observed positron excess. These decays
can naturally take place via GUT interactions. If it exists, such a
metastable particle can be found in the next run of LHC. The model
predicts also the ratio of leptons over baryons in the universe to be close to .
