Combination of top pair production cross section measurements

We present a combination of the measurements of the $pp \to t\overline{t}$ production cross section at $\sqrt{s}=7$ TeV using data collected by the CMS detector at the Large Hadron Collider. The channels included in the combination are single lepton ($e/\mu$+jets), dilepton ($ee$, $\mu\mu$, $e\mu$), tau ($\mu \tau$), and fully hadronic decays. The analyses use data corresponding to an integrated luminosity between 0.8 and 1.1 fb$^{-1}$. A binned maximum likelihood fitter is used for the combination. We find a combined cross section of $\sigma_{\ttbar} = 165.8 \pm 2.2 \mathrm{(stat.)} \pm 10.6 \mathrm{(syst.)} \pm 7.8 \mathrm{(lumi.)}\;\mathrm{pb}.$