Measurement of the W-boson mass in the ATLAS experiment at the LHC

The measurement of the W -boson mass in proton–proton collisions in the ATLAS experiment at the Large Hadron Collider (LHC) provides a consistency test of the Standard Model and a probe of Beyond the Standard Model physics. A first measurement of the W-boson mass at the LHC is presented in this proceeding. The measurement of the W -boson mass is performed with leptonic decays of the W -boson. The data is recorded in 2011 at a centre-of-mass energy of 7 TeV with the ATLAS detector at the LHC. The combined result of the W-boson mass is measured to be 80369.5 $\pm$ 18.5 MeV where the total uncertainty includes the statistical, experimental systematic, and physics-modelling systematic uncertainty. The mass difference between positive charged W -bosons and negative charged W -bosons is measured to be −29 $\pm$ 28 MeV.