Measurement of the angular distribution of electrons from W→eν decays observed in pp̅ collisions at √s=1.8 TeV

Abstract

We present the first measurement of the electron angular distribution parameter α₂ in W→eν 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±α₁cosθ^∗+α₂cos²θ^∗), where θ^∗ is the polar angle of the electron in the Collins-Soper frame. In the presence of QCD corrections, the parameters α₁ and α₂ 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.