Combination of ATLAS and CMS results on the mass of the top-quark using up to 4.9 $\it{fb}^{-1}$ of $\sqrt{s} = 7$ TeV LHC data

A combination of top-quark mass measurements performed by the ATLAS and CMS experimentsat the LHC is presented. The datasets used correspond to an integrated luminosityper experiment of up to 4.9 fb1 of proton-proton collisions at a centre-of-mass energy of7 TeV. The combination includes measurements in the t¯t ! lepton+jets, t¯t ! di-lepton andt¯t ! all jets channels. The resulting combined LHC measurement of the top-quark mass ismtop = 173:29 0:23 (stat) 0:92 (syst) GeV, with a total uncertainty of 0:95 GeV