  We report on a preliminary measurement of the ratio of the differential cross
sections for W and Z boson production as a function of transverse momentum in
proton-antiproton collisions at $\sqrt{s}$ = 1.8 TeV. It has been shown that
the ratio between W and Z observables can be reliably calculated using
perturbative QCD, even when the individual observables are not. We present the
first comparison between the measurement of a W and Z observable ratio and a
purely perturbative calculation. The use of the ratio reduces both experimental
and theoretical uncertainites and might result in smaller overall uncertainties
on the measured W mass and width, compared to currently used methods at hadron
colliders.
