Measurement of the W-boson mass in pp collisions at $\sqrt{s}=7\phantom{\rule{0.166667em}{0ex}}\text{TeV}$ with the ATLAS detector

A measurement of the mass of the W boson is presented based on proton–proton collision data recorded in 2011 at a centre-of-mass energy of 7 TeV with the ATLAS detector at the LHC, and corresponding to $4.6\phantom{\rule{3.33333pt}{0ex}}{\text{fb}}^{-1}$ of integrated luminosity. The selected data sample consists of $7.8×{10}^{6}$ candidates in the $W\to \mu \nu $ channel and $5.9×{10}^{6}$ candidates in the $W\to e\nu $ channel. The W-boson mass is obtained from template fits to the reconstructed distributions of the charged lepton transverse momentum and of the W boson transverse mass in the electron and muon decay channels, yielding $\begin{array}{cc}{m}_{W}=80370& ±7\phantom{\rule{3.33333pt}{0ex}}\left(\text{stat.}\right)±11\left(\text{exp. syst.}\right)\\ & ±14\phantom{\rule{3.33333pt}{0ex}}\left(\text{mod. syst.}\right)\phantom{\rule{3.33333pt}{0ex}}\text{MeV}\\ =80370& ±19\phantom{\rule{0.166667em}{0ex}}\text{MeV},\end{array}$ where the first uncertainty is statistical, the second corresponds to the experimental systematic uncertainty, and the third to the physics-modelling systematic uncertainty. A measurement of the mass difference between the ${W}^{+}$ and ${W}^{-}$ bosons yields ${m}_{{W}^{+}}-{m}_{{W}^{-}}=-\phantom{\rule{0.166667em}{0ex}}29±28$ MeV.