Top pair cross section in e/mu+jets at 8 TeV

A measurement is presented of the top quark pair-production cross section in $\sqrt{s} =$~8~TeV proton-proton collisions using data corresponding to an integrated luminosity of up to 2.8~fb$^{-1}$, collected by the CMS detector at the Large Hadron Collider. The analysis is performed in the top quark pair decay channel with one isolated, high transverse momentum electron or muon, and at least four hadronic jets. At least one jet is required to originate from a b-quark. The measured inclusive $\mathrm{t\overline{t}}$ cross section is: $ \sigma_\mathrm{t\overline{t}} = 228.4 \pm 9.0 {\rm~(stat.)} ^{+29.0}_{-26.0} {\rm~(syst.)} \pm 10.0 {\rm~(lum.)} \,\rm{pb}$, in agreement with QCD predictions up to approximate next-to-next-to-leading order.