Test of scaling of the massive-dihadron cross section

Measurements of the cross section for production of massive dihadrons by 800-GeV protons incident on a tungsten target are presented. These are compared with measurements taken at lower and higher $\sqrt{s}$ and with perturbative-QCD predictions. Scaling and $A$-dependence behaviors observed at lower energies are confirmed, and good agreement with QCD is obtained. Model dependences of earlier measurements are discussed.