Updated cosmic-ray and radio constraints on light dark matter:
  Implications for the GeV gamma-ray excess at the Galactic center
  The apparent gamma-ray excess in the Galactic center region and inner Galaxy
has attracted considerable interest, notably because both its spectrum and
radial distribution are consistent with an interpretation in terms of
annihilating dark matter particles with a mass of about 10-40 GeV. We confront
such an interpretation with an updated compilation of various indirect dark
matter detection bounds, which we adapt to the specific form required by the
observed signal. We find that cosmic-ray positron data strongly rule out dark
matter annihilating to light leptons, or 'democratically' to all leptons, as an
explanation of the signal. Cosmic-ray antiprotons, for which we present
independent and significantly improved limits with respect to previous
estimates, are already in considerable tension with DM annihilation to any
combination of quark final states; the first set of AMS-02 data will thus be
able to rule out or confirm the DM hypothesis with high confidence. For
reasonable assumptions about the magnetic field in the Galactic center region,
radio observations independently put very severe constraints on a DM
interpretation of the excess, in particular for all leptonic annihilation
channels.
