Combination of CDF and D0 results on the $W$ boson mass and width

The results based on 1992–95 data (Run 1) from the CDF and D0 experiments on the measurements of the $W$ boson mass and width are presented, along with the combined results. We report a Tevatron collider average $M_W=80.456\pm 0.059\mathrm{G}\mathrm{e}\mathrm{V}$. We also report the Tevatron collider average of the directly measured $W$ boson width ${\Gamma }_W=2.115\pm 0.105\mathrm{G}\mathrm{e}\mathrm{V}$. We describe a new joint analysis of the direct $W$ mass and width measurements. Assuming the validity of the standard model, we combine the directly measured $W$ boson width with the width extracted from the ratio of $W$ and $Z$ boson leptonic partial cross sections. This combined result for the Tevatron is ${\Gamma }_W=2.135\pm 0.050\mathrm{G}\mathrm{e}\mathrm{V}$. Finally, we use the measurements of the direct total $W$ width and the leptonic branching ratio to extract the leptonic partial width $\Gamma (W\to e\nu )=224\pm 13\mathrm{M}\mathrm{e}\mathrm{V}$.

Figure 1

Direct measurements of the $W$ boson mass compared with the SM prediction [22] based on a fit to all $Z$-pole data and the direct top mass measurements.

Figure 2

Direct measurements of the $W$ boson width compared with the SM prediction [23].