Measurement of the Top Quark Pair Production Cross Section in Proton-Proton Collisions at $\sqrt{s}=13\mathrm{TeV}$

The top quark pair production cross section is measured for the first time in proton-proton collisions at $\sqrt{s}=13\mathrm{TeV}$ by the CMS experiment at the CERN LHC, using data corresponding to an integrated luminosity of $43{\mathrm{pb}}^{-1}$. The measurement is performed by analyzing events with at least one electron and one muon of opposite charge, and at least two jets. The measured cross section is $746\pm 58(\text{stat})\pm 53(\text{syst})\pm 36(\text{lumi})\mathrm{pb}$, in agreement with the expectation from the standard model.

Figure 1

The distributions in (top) the jet multiplicity, and (bottom) $H_{\mathrm{T}}$ in events passing the dilepton criteria. The expected distributions for $t\overline{t}$ signal and individual backgrounds are shown after implementing data-based corrections; the last bin contains the overflow events. The ratios of data to the sum of the expected yields are given at the bottom of each panel.

Figure 2

The distributions in (top) the dilepton invariant mass, and (bottom) the difference in the azimuthal angle between the two leptons after all selections. The last bin in (top) contains the overflow events. The ratios of data to the sum of the expected yields are given at the bottom of each panel.