This Letter describes a direct measurement of the $W$ boson decay width, $\Gamma \mathrm{}\left(W\right)\mathrm{}$, using the high-mass tail of the transverse mass spectrum of $W\to e\nu$ decays recorded by the Collider Detector at Fermilab. We find $\Gamma \mathrm{}\left(W\right)=2.11\mathrm{}\pm 0.28\left(\mathrm{stat}\right)\pm 0.16\left(\mathrm{syst}\right)$ GeV and compare this direct measurement with indirect means of obtaining the width.

• Received 9 September 1994

DOI:https://doi.org/10.1103/PhysRevLett.74.341