First run II 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 at the Fermilab Tevatron

Abstract

We describe a measurement of the $W$ boson mass ${m}_{W}$ using $200\text{ }\text{ }{\mathrm{pb}}^{\ensuremath{-}1}$ of $\sqrt{s}=1.96\text{ }\text{ }\mathrm{TeV}$ $p\overline{p}$ collision data taken with the CDF II detector. With a sample of 63 964 $W\ensuremath{\rightarrow}e\ensuremath{\nu}$ candidates and 51 128 $W\ensuremath{\rightarrow}\ensuremath{\mu}\ensuremath{\nu}$ candidates, we measure ${m}_{W}=[80.413\ifmmode\pm\else\textpm\fi{}0.034(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.034(\mathrm{sys})=80.413\ifmmode\pm\else\textpm\fi{}0.048]\text{ }\text{ }\mathrm{GeV}/{c}^{2}$. This is the single most precise ${m}_{W}$ measurement to date. When combined with other measured electroweak parameters, this result further constrains the properties of new unobserved particles coupling to $W$ and $Z$ bosons.