Observation of $\mathrm{t}\overline{\mathrm{t}}\mathrm{H}$ production at CMS

The observation of Higgs boson production in association with a top quark-antiquark pair is reported, based on a combined analysis of proton-proton collision data at center-of-mass energies of $\sqrt{s}=7$, 8 and 13 TeV, corresponding to integrated luminosities of up to 5.1, 19.7, and 35.9 fb${}^{-1}$, respectively. The data were collected with the CMS detector at the CERN LHC. An excess of events is observed with a significance of 5.2 standard deviations over the expectation from the background-only hypothesis. The corresponding expected significance from the standard model for a Higgs boson mass of 125.09 GeV is 4.2 standard deviations. The combined best fit signal strength normalised to the standard model prediction is $1.26^{+0.31}_{-0.26}$.