Top pair cross section in dileptons

The cross section for top quark pair production is measured in proton-proton collisions at $\sqrt{s} = 8\rm~TeV$ in a data sample corresponding to 2.4 inverse femtobarns of integrated luminosity collected by the CMS experiment in 2012. The measurement is performed with events with two leptons (electrons or muons) as well as with identified b-quark jets in the final state. The combined measured cross section is 227 $\pm$ 3 (stat.) $\pm$ 11 (syst.) $\pm$ 10 (lumi.) pb, in agreement with theoretical predictions.