Measurement of Dijet Angular Distributions and Search for Quark Compositeness

We have measured the dijet angular distribution in $\sqrt{s}=1.8\mathrm{TeV}p\overline{p}$ collisions using the D0 detector. Order ${\alpha }_s^3$ QCD predictions are in good agreement with the data. At 95% confidence limit the data exclude models of quark compositeness in which the contact interaction scale is below 2 TeV.