This review presents the world's most precise measurement of the W-boson mass mW using data corresponding to ≈ 2.2 fb-1 integrated luminosity collected with the CDF II detector at Fermi National Accelerator Laboratory (Fermilab). With samples of 470,126 W → eν candidates and 624,708 W → μν candidates, mW is measured to be 80387±12 stat ± 15 syst = 80387 ± 19 MeV [Phys. Rev. Lett.108, 151803 (2012)]. This result significantly exceeds the precision of all previous measurements and improves the world averaged precision by 30%.
Measurement of the W boson helicity in top-antitop quark events with the CDF II experiment