Fermi-LAT kills dark matter interpretations of AMS-02 data. Or not?
  A number of papers attempt to explain the positron anomaly in cosmic rays,
observed by PAMELA and AMS-02, in terms of dark matter (DM) decays or
annihilations. However, the recent progress in cosmic gamma-ray studies
challenges these attempts. Indeed, as we show, any rational DM model explaining
the positron anomaly abundantly produces final state radiation and Inverse
Compton gamma rays, which inevitably leads to a contradiction with Fermi-LAT
isotropic diffuse gamma-ray background measurements. Furthermore, the Fermi-LAT
observation of Milky Way dwarf satellites, supposed to be rich in DM, revealed
no significant signal in gamma rays. We propose a generic approach in which the
major contribution to cosmic rays comes from the dark matter disc and prove
that the tension between the DM origin of the positron anomaly and the cosmic
gamma-ray observations can be relieved. We consider both a simple model, in
which DM decay/annihilate into charged leptons, and a model-independent minimal
case of particle production, and we estimate the optimal thickness of DM disk.
Possible mechanisms of formation and its properties are briefly discussed.
