This Letter describes a direct measurement of the 𝑊 boson total decay width, 𝛤𝑊, using the Collider Detector at Fermilab. The measurement uses an integrated luminosity of 90⁢pb−1, collected during the 1994–1995 run of the Fermilab Tevatron 𝑝⁢¯𝑝 collider. The width is determined by normalizing predicted signal and background distributions to 49 844 𝑊 →𝑒⁢𝜈 candidates and 21 806 𝑊 →𝜇⁢𝜈 candidates in the transverse-mass region 𝑀𝑇 <200 GeV and then fitting the predicted shape to the 438 electron events and 196 muon events in the high- 𝑀𝑇 region, 100 <𝑀𝑇 <200 GeV. The result is 𝛤𝑊 = 2.04 ±0.11⁢(stat) ±0.09⁢(syst)⁢GeV.

This work is supported by the U.S. Department of Energy, the National Science Foundation, the Natural Sciences and Engineering Research Council of Canada, the Instituto Nazionale di Fisica Nucleare of Italy, the Ministry of Education, Science and Culture of Japan, the National Science Council of the Republic of China, and the A.P. Sloan Foundation.

CDF Collaboration: et al.

Peer reviewed