  The Higgs boson decay into a pair of real or virtual W bosons, with one of
them decaying leptonically, is predicted within the Standard Model to have the
largest branching fraction of all Higgs decays that involve an isolated
electron or muon, for M_h > 120 GeV. We compute analytically the
fully-differential width for this h -> l \nu jj decay at tree level, and then
explore some multi-dimensional cuts that preserve the region of large signal.
Future searches for semileptonic decays at the Tevatron and LHC, employing
fully-differential information as outlined here, may be essential for ruling
out or in the Higgs boson and for characterizing a Higgs signal.
