"Non-Local" Effects from Boosted Dark Matter in Indirect Detection
  Indirect dark matter (DM) detection typically involves the observation of
standard model (SM) particles emerging from DM annihilation/decay inside
regions of high dark matter concentration. We consider an annihilation scenario
in which this reaction has to be initiated by one of the DMs involved being
boosted while the other is an ambient non-relativistic particle. This "trigger"
DM must be created, for example, in a previous annihilation or decay of a
heavier component of DM. Remarkably, boosted DM annihilating into gamma-rays at
a specific point in a galaxy could actually have traveled from its source at
another point in the same galaxy or even from another galaxy. Such a
"non-local" behavior leads to a non-trivial dependence of the resulting photon
signal on the galactic halo parameters, such as DM density and core size,
encoded in the so-called "astrophysical" $J$-factor. These non-local
$J$-factors are strikingly different than the usual scenario. A distinctive
aspect of this model is that the signal from dwarf galaxies relative to the
Milky Way tends to be suppressed from the typical value to various degrees
depending on their characteristics. This feature can thus potentially alleviate
the mild tension between the DM annihilation explanation of the observed excess
of $\sim$ GeV photons from the Milky Way's galactic center vs. the apparent
non-observation of the corresponding signal from dwarf galaxies.
