  We present a preliminary measurement of the electron angular distribution
parameter alpha2 in W to e nu events using data collected by the D0 detector
during the 1994--1995 Tevatron run. We compare our results with next-to-leading
order perturbative QCD, which predicts an angular distribution of 1 +/- alpha1
cos theta* +alpha_2 cos^2 theta*, where theta* is the angle between the charged
lepton and the antiproton in the Collins-Soper frame. In the presence of QCD
corrections, the parameters alpha1 and alpha2 become functions of pT(W), the W
boson transverse momentum. We present the first measurement of alpha_2 as a
function of pT(W). This measurement is of importance, because it provides a
test of next-to-leading order QCD corrections which are a non-negligible
contribution to the W mass measurement.
