  We propose the measurement of the ratio $R_{CSS}(Q_T^{\min}) \equiv
\frac{\sigma (Q_T>Q_T^{\min})}{\sigma _{Total}}$ to study the effects of the
multiple soft gluon radiation, predicted by QCD, on the transverse momentum
($Q_T$) distribution of the weak gauge bosons $W^{\pm }$ and $Z^0$ produced at
the Tevatron. We compare the prediction of the extended Collins-Soper-Sterman
resummation formalism with the next-to-leading and next-to-next-to-leading
order calculations. We show that both the rich dynamics of the QCD multiple
soft gluon radiation and the non-perturbative sector of QCD can be tested by
measuring $R_{CSS}$.
