Measurement of the top quark pair production cross section in proton-proton collisions at sqrt(s)=13 TeV with the CMS detector

The top-antitop quark (${\rm t}{\bar{\rm t}}$) production cross section is measured for the first time by the CMS experiment in proton-proton collisions at $\sqrt{s} = 13\, {\rm TeV}$ at the CERN LHC, using data corresponding to an integrated luminosity of $42\, {\rm pb}^{-1}$. The measurement is performed by analyzing events with one electron and one muon and at least two jets. The measured cross section is $\sigma_{{\rm t}{\bar{\rm t}}} = 772 \pm 60\, {\rm (stat)} \pm 62\, {\rm (syst)} \pm 93\, {\rm (lumi)}\, {\rm pb}$, in agreement with the expectations from the standard model.