Combination of W boson polarization measurements in top quark decays using ATLAS and CMS data at 8 TeV

Measurements of the inclusive top-quark pair production cross section and of the W boson polarisation in top quark decays are presented. The most precise results performedd by the ATLAS and CMS collaborations using all the proton-proton collisions data produced at the LHC at center-of-mass energies of 7 and 8 Te. The combined results provide both lower uncertainties than the individual measurements and stringent comparisons with the standard model predictions at NNLO in perturbative QCD.