In Wino Veritas? Indirect Searches Shed Light on Neutralino Dark Matter
  Indirect detection constraints on gamma rays (both continuum and lines) have
set strong constraints on wino dark matter. By combining results from Fermi-LAT
and HESS, we show that: light nonthermal wino dark matter is strongly excluded;
thermal wino dark matter is allowed only if the Milky Way dark matter
distribution has a significant (>~0.4 kpc) core; and for plausible NFW and
Einasto distributions the entire range of wino masses from 100 GeV up to 3 TeV
can be excluded. The case of light, nonthermal wino dark matter is particularly
interesting in scenarios with decaying moduli that reheat the universe to a low
temperature. Typically such models have been discussed for low reheating
temperatures, not far above the BBN bound of a few MeV. We show that
constraints on the allowed wino relic density push such models to higher
reheating temperatures and hence heavier moduli. Even for a flattened halo
model consisting of an NFW profile with constant-density core inside 1 kpc and
a density near the sun of 0.3 GeV/cm^3, for 150 GeV winos current data
constrains the reheat temperature to be above 1.4 GeV. As a result, for models
in which the wino mass is a loop factor below the gravitino mass, the data
favor moduli that are more than an order of magnitude heavier than the
gravitino. We discuss some of the sobering implications of this result for the
status of supersymmetry. We also comment on other neutralino dark matter
scenarios, in particular the case of mixed bino/higgsino dark matter. We show
that in this case, direct and indirect searches are complementary to each other
and could potentially cover most of the parameter space.
