Measurement of the angular distribution of electrons from $\overrightarrow{W}e\nu$ decays observed in $p\overline{p}$ collisions at $\sqrt{s}=1.8\mathrm{}$ TeV

We present the first measurement of the electron angular distribution parameter ${\alpha }_2$ in $\overrightarrow{W}e\nu$ events produced in proton-antiproton collisions as a function of the W boson transverse momentum. Our analysis is based on data collected using the DØ detector during the 1994–1995 Fermilab Tevatron run. We compare our results with next-to-leading order perturbative QCD, which predicts an angular distribution of $(1\mathrm{}\pm {\alpha }_1\cos {\theta }^{*}+{\alpha }_2{\cos }^2{\theta }^{*}),$ where ${\theta }^{*}$ is the polar angle of the electron in the Collins-Soper frame. In the presence of QCD corrections, the parameters ${\alpha }_1$ and ${\alpha }_2$ become functions of $p_T^W,$ the W boson transverse momentum. This measurement provides a test of next-to-leading order QCD corrections which are a non-negligible contribution to the W boson mass measurement.