Measurement of the $ \mathrm{t}\overline{\mathrm{t}} $ production cross section in the all-jet final state in pp collisions at $ \sqrt{s}=7 $ TeV

A measurement is presented of the $ \mathrm{t}\overline{\mathrm{t}} $ production cross section $ \left( {{\sigma_{{\mathrm{t}\overline{\mathrm{t}}}}}} \right) $ in proton-proton collisions at a centre-of-mass energy of 7 TeV, in the all-jet final state that contains at least six jets, two of which are tagged as originating from b quarks. The data correspond to an integrated luminosity of 3.54 fb−1, collected with the CMS detector at the LHC. The cross section is determined through an unbinned maximum likelihood fit of background and $ \mathrm{t}\overline{\mathrm{t}} $ signal to the reconstructed mass spectrum of $ \mathrm{t}\overline{\mathrm{t}} $ candidates in the data, in which events are subjected to a kinematic fit assuming a $ \mathrm{t}\overline{\mathrm{t}}\to {{\mathrm{W}}^{+}}\mathrm{b}{{\mathrm{W}}^{-}}\overline{\mathrm{b}}\to 6 $ jets hypothesis. The measurement yields $ {\sigma_{{\mathrm{t}\overline{\mathrm{t}}}}}=139\pm 10\;\left( {\mathrm{stat}.} \right)\pm 26\;\left( {\mathrm{syst}.} \right)\pm 3\left( {\mathrm{lum}.} \right)\;\mathrm{pb} $ , a result consistent with those obtained in other $ \mathrm{t}\overline{\mathrm{t}} $ decay channels, as well as with predictions of the standard model.