  We present a reanalysis of the latest results from CMS dijet searches for an
integrated luminosity of $36\,$fb$^{-1}$ together with preliminary results for
$78\,$fb$^{-1}$ in the framework of simplified models for dark matter
interacting with quarks through the exchange of a scalar, pseudoscalar, vector
or pseudovector mediator particle. Within the same framework, we also project
the sensitivity of dijet searches in future LHC runs and study how well the
parameters of a simplified model could be reconstructed in case of a future
discovery at the high luminosity (HL) LHC. Finally, we explore the possibility
of discriminating different mediator scenarios by extending the sensitivity of
dijet searches for simplified models through the use of angular information. It
is the first time that these studies are performed systematically for the case
of spin 0 mediators. Among other results we find: 1) no evidence for a dijet
signal in the simplified model framework; 2) improvements due to an increased
luminosity at the HL-LHC are significant, but mostly for heavy mediators, where
dijet searches are limited by statistical, rather than systematical
uncertainties; 3) Information on the angular separation of dijets could be used
at the HL-LHC to discriminate different mediator scenarios.
