Wino Dark Matter Under Siege
  A fermion triplet of SU(2)_L - a wino - is a well-motivated dark matter
candidate. This work shows that present-day wino annihilations are constrained
by indirect detection experiments, with the strongest limits coming from
H.E.S.S. and Fermi. The bounds on wino dark matter are presented as a function
of mass for two scenarios: thermal (winos constitute a subdominant component of
the dark matter for masses less than 3.1 TeV) and non-thermal (winos comprise
all the dark matter). Assuming the NFW halo model, the H.E.S.S. search for
gamma-ray lines excludes the 3.1 TeV thermal wino; the combined H.E.S.S. and
Fermi results completely exclude the non-thermal scenario. Uncertainties in the
exclusions are explored. Indirect detection may provide the only probe for
models of anomaly plus gravity mediation where the wino is the lightest
superpartner and scalars reside at the 100 TeV scale.
