We present the first measurement of the A_2 and A_3 angular
coefficients of the W boson produced in proton-antiproton collisions. We
study W --> e nu_e and W --> mu nu(mu) candidate events produced in association
with at least one jet at CDF, during Run Ia and Run Ib of the Tevatron at
s**(1/2) = 1.8 TeV. The corresponding integrated luminosity was 110 pb-1.
The jet balances the transverse momentum of the W and introduces QCD effects
in W boson production. The extraction of the angular coefficients is
achieved through the direct measurement of the azimuthal angle of the
charged lepton in the Collins-Soper rest-frame of the W boson. The angular
coefficients are measured as a function of the transverse momentum of the W
boson. The electron, muon, and combined results are in good agreement with
the Standard Model prediction, up to order alpha2_s in QCD.
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Updated: Wednesday, 2006 April 19 16:03:08 CDT automatically from input from Carol Picciolo