  We discuss the extent to which models of Weakly Interacting Massive Particle
(WIMP) Dark Matter (DM) at and above the electroweak scale can be probed
conclusively in future high energy and astroparticle physics experiments. We
consider simplified models with bino-like dark matter and slepton-like
coannihilation partners, and find that perturbative models yield the observed
relic abundance up to at least 10 TeV. We emphasise that coannihilation can
either increase or decrease the dark matter relic abundance. We compute the
sensitivity of direct detection experiments to DM-nucleus scattering, consider
indirect detection bounds and estimate the sensitivity of future proton
colliders to slepton pair production. We find that current and future
experiments will be able to probe the Dirac DM models up to at least 10 TeV.
However, current and future searches will not be sensitive to models of
Majorana dark matter for masses above 2 or 4 TeV, for one or ten coannihilation
partners respectively, leaving around 70 % of the parameter space
unconstrained. This demonstrates the need for new experimental ideas to access
models of coannihilating Majorana dark matter.
