Measurement of the azimuthal angle distribution of leptons from W boson decays as a function of the W transverse momentum in p(p)over-bar collisions at root s = 1.8 TeV

We present the first measurement of the A2 and A3 angular coefficients of the W boson produced in proton-antiproton collisions. We study W→eνe and W→μνμ candidate events produced in association with at least one jet at CDF, during Run Ia and Run Ib of the Tevatron at s=1.8TeV. The corresponding integrated luminosity was 110pb-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 αs2 in QCD.