  We study a scenario in which the only light new particles are a Majorana
fermion dark matter candidate and one or more QCD-charged scalars, which couple
to light quarks. This scenario has several interesting phenomenological
features if the new particles are nearly degenerate in mass. In particular, LHC
searches for the light scalars have reduced sensitivity, since the visible and
invisible products tend to be softer. Moreover, dark matter-scalar
co-annihilation can allow even relatively heavy dark matter candidates to be
consistent thermal relics. Finally, the dark matter nucleon scattering cross
section is enhanced in the quasi-degenerate limit, allowing direct detection
experiments to use both spin-independent and spin-dependent scattering to probe
regions of parameter space beyond those probed by the LHC. Although this
scenario has broad application, we phrase this study in terms of the MSSM, in
the limit where the only light sparticles are a bino-like dark matter candidate
and light-flavored squarks.
