First experimental results are presented from a search for events with
a rapidity gap between jets. The DO detector was used to examine even
ts produced by the Fermilab Tevatron ppBAR collider at square-root s =
1.8 TeV. The fraction of events with an observed rapidity gap between
the two highest transverse energy (E(T)) jets is measured as a functi
on of the pseudorapidity separation between the jet edges (DELTAeta(c)
). An upper limit at the 95% confidence level of 1.1 X 10(-2) is obtai
ned on the fraction of events with no particles between the jets, for
events with DELTAeta(c) > 3 and jet E(T) greater than 30 GeV.