Closing up on dark sectors at colliders: From 14 to 100 TeV

We investigate the reach of the LHC Run 2 and that of a future circular hadron collider with up to 100 TeV center of mass energy for the exploration of potential dark matter sectors. These dark sectors are conveniently and broadly described by simplified models. The simplified models we consider provide microscopic descriptions of interactions between the standard model partons and the dark sector particles mediated by the four basic types of (s-channel) messenger fields: scalar, pseudoscalar, vector or axial-vector. Our analysis extends and updates the previously available results for the LHC at 8 and 14 TeV to 100 TeV for models with all four messenger types. We revisit and improve the analysis at 14 TeV, by studying a variety of analysis techniques, concluding that the most discriminating variables correspond to the missing transverse energy and the azimuthal angle between jets in the final state. Going to 100 TeV, the limits on simplified models of dark matter are enhanced significantly, in particular for heavier mediators and dark sector particles, for which the available phase space at the LHC is restricted. The possibility of a 100 TeV collider provides an unprecedented coverage of the dark sector basic parameters and a unique opportunity to pin down the particle nature of dark matter and its interactions with the standard model.