Combination of ATLAS and CMS results on the mass of the top quark using up to 4.9 inverse femtobarns of data

A combination of top-quark mass measurements performed by the ATLAS and CMS experiments at the LHC is presented. The dataset used corresponds to an integrated luminosity per experiment of up to 4.9 $\rm{fb}^{-1}$ of proton-proton collisions at a centre-of-mass energy of 7 TeV. The combination includes measurements in the ${\rm{t \bar{t}}\to\mbox{lepton+jets}}$, ${\rm{t \bar{t}}\to\mbox{di-lepton}}$ and ${\rm{t \bar{t}}\to\mbox{all jets}}$ channels. The resulting combined LHC measurement of the top-quark mass is $m_{t} = 173.29 \pm 0.23 \mbox{ (stat)} \pm 0.92 \mbox{ (syst)}$ GeV, with a total uncertainty of $0.95$ GeV.