Direct Measurement of the W Boson Width in ppbar Collisions at roots = 1.8 TeV

TL;DR

This paper reports a direct measurement of the W boson decay width using proton-antiproton collision data at Fermilab, achieving a precise value through shape fitting of transverse mass distributions.

Contribution

It presents the first direct measurement of the W boson width at Fermilab using high-statistics collider data and shape analysis techniques.

Findings

Measured W boson width: 2.04 GeV with combined uncertainty

Used 90 pb^{-1} of data from Fermilab Tevatron run

Achieved improved precision over previous indirect estimates

Abstract

This Letter describes a direct measurement of the $W$ boson total decay width, $\gw$, using the Collider Detector at Fermilab. The measurement uses an integrated luminosity of $90\invpb$, collected during the 1994--1995 run of the Fermilab Tevatron $p\pbar$ collider. The width is determined by normalizing predicted signal and background distributions to 49844 $\wenu$ candidates and 21806 $\wmunu$ candidates in the transverse-mass region $M_T<200\gev$ and then fitting the predicted shape to the 438 electron events and 196 muon events in the high-$M_T$ region, $100<M_T<200\gev$. The result is $\Gamma_W=2.04\pm0.11$(stat)$\pm0.09$(syst)GeV.