Heavy Higgs Boson Production in Association with Three Jets at Hadron Supercolliders

We consider the real emission QCD correction to heavy Higgs boson production via weak boson fusion in high energy $pp$ collisions. The ${\cal O}(\alpha_s)$ corrections are determined for the complete electroweak $q q \rightarrow q q W^+ W^-$ process. The presence of a third parton in the final state affects the formation of rapidity gaps only slightly. In particular, soft emission into the gap region is severely suppressed. Also, we investigate how the additional hard emission affects forward-jet-tagging and central-jet-vetoing efficiencies in the search for $H \rightarrow W^+ W^- \rightarrow \ell^+ \nu \ell^- \bar{\nu}$ decays.