Search for dark matter particles produced in association with a top quark pair at $\sqrt{s} =$ 13 TeV

Understand

A search is performed for dark matter particles produced in association with a top quark pair in proton-proton collisions at $\sqrt{s} =$ 13 TeV.

• The data correspond to an integrated luminosity of 35.9 fb$^{-1}$ recorded by the CMS detector at the LHC.
• No significant excess over the standard model expectation is observed.
• The results are interpreted using simplified models of dark matter production via spin-0 mediators that couple to dark matter particles and to standard model quarks, providing constraints on the coupling strength between the mediator and the quarks.