Direct Measurement of the W Boson Width

Abstract

We present a direct measurement of the width of the W boson using the shape of the transverse mass distribution of W→eν candidate events. Data from approximately 1 fb(−1) of integrated luminosity recorded at s√=1.96 TeV by the D0 detector at the Fermilab Tevatron pp-bar collider are analyzed. 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.