  We study the discrimination of quark-initiated jets from gluon-initiated jets
in monojet searches for dark matter using the technique of averaged jet energy
profiles. We demonstrate our results in the context of effective field theories
of dark matter interactions with quarks and gluons, but our methods apply more
generally to a wide class of models. Different effective theories of dark
matter and the standard model backgrounds each have a characteristic
quark/gluon fraction for the leading jet. When used in conjunction with the
traditional cut-and-count monojet search, the jet energy profile can be used to
set stronger bounds on contact interactions of dark matter. In the event of a
discovery of a monojet excess at the 14 TeV LHC, contact interactions between
dark matter with quarks or with gluons can be differentiated at the 95%
confidence level. For a given rate at the LHC, signal predictions at direct
detection experiments for different dark matter interactions can span five
orders of magnitude. The ability to identify these interactions allows us to
make a tighter connection between LHC searches and direct detection
experiments.
