Precise Measurement of the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>W</mml:mi></mml:math>-Boson Mass with the CDF II Detector

Abstract

We have measured the $W$-boson mass ${M}_{W}$ using data corresponding to $2.2\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ of integrated luminosity collected in $p\overline{p}$ collisions at $\sqrt{s}=1.96\text{ }\text{ }\mathrm{TeV}$ with the CDF II detector at the Fermilab Tevatron collider. Samples consisting of 470 126 $W\ensuremath{\rightarrow}e\ensuremath{\nu}$ candidates and 624 708 $W\ensuremath{\rightarrow}\ensuremath{\mu}\ensuremath{\nu}$ candidates yield the measurement ${M}_{W}=80\text{ }387\ifmmode\pm\else\textpm\fi{}{12}_{\mathrm{stat}.}\ifmmode\pm\else\textpm\fi{}{15}_{\mathrm{syst}.}=80\text{ }387\ifmmode\pm\else\textpm\fi{}19\text{ }\text{ }\mathrm{MeV}/{c}^{2}$. This is the most precise measurement of the $W$-boson mass to date and significantly exceeds the precision of all previous measurements combined.