Jet Production via Strongly Interacting Color-Singlet Exchange inpp¯Collisions

A study of the particle multiplicity between jets with large rapidity separation has been performed using the D0 detector at the Fermilab Tevatron $p\overline{p}$ Collider operating at $\sqrt{s}=1.8\mathrm{}\mathrm{TeV}$. A significant excess of low-multiplicity events is observed above the expectation for color-exchange processes. The measured fractional excess is $1.07\pm 0.10\left(\mathrm{stat}{)}_{-0.13\mathrm{}}^{+0.25\mathrm{}}\right(\mathrm{syst})\%$, which is consistent with a strongly interacting color-singlet (colorless) exchange process and cannot be explained by electroweak exchange alone. A lower limit of $0.80\%$ (95% C.L.) is obtained on the fraction of dijet events with color-singlet exchange, independent of the rapidity gap survival probability.