Measurement of the angular distribution of electrons from W⃗ eν decays observed in pp-bar collisions at s√=1.8 TeV

Abstract

We present the first measurement of the electron angular distribution parameter α(2) in W⃗ 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±α(1c)osθ*+α(2)cos(2)θ*), where θ* is the polar angle of the electron in the Collins-Soper frame. In the presence of QCD corrections, the parameters α(1) and α(2) become functions of pWT, 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.