Direct measurement of the W boson width

2009

We present a direct measurement of the width of the W boson using the shape of the transverse mass distribution of W->enu candidates selected in 1 fb-1 of data collected with the D0 detector at the Fermilab Tevatron collider in ppbar collisions at sqrt{s}=1.96 TeV. We use the same methods and data sample that were used for our recently published W boson mass measurement, except for the modeling of the recoil, which is done with a new method based on a recoil library. Our result, 2.028 +- 0.072 GeV, is in agreement with the predictions of the standard model.