Measurement of the W boson mass

Abstract

We present a measurement of the W boson mass in W -> ev decays using 1 fb^-1 of data collected with the D0 detector during Run II of the Fermilab Tevatron collider. With a sample of 499830 W -> ev candidate events, we measure M_W = 80.401 +- 0.043 GeV. This is the most precise measurement from a single experiment.

Figures (2)

• Figure 1: (a) The dielectron invariant mass distribution in $Z\to ee$ data and from the fast simulation fastmc and (b) the $\chi$ values where $\chi_i = [N_i-\,($ fastmc$_i)]/\sigma_i$ for each point in the distribution, $N_i$ is the data yield in bin $i$ and $\sigma_i$ is the statistical uncertainty in bin $i$.
• Figure 2: The (a) $m_T$, (b) $p_T^e$, and (c) ${\slash emE}_{T}$ distributions for data and fastmc simulation with backgrounds. The $\chi$ values are shown below each distribution where $\chi_i = [N_i-\,($ fastmc$_i)]/\sigma_i$ for each point in the distribution, $N_i$ is the data yield in bin $i$ and only the statistical uncertainty is used. The fit ranges are indicated by the double-ended horizontal arrows.