Nonstandard Higgs Decays with Visible and Missing Energy

Experimental and theoretical clues both suggest that the Higgs boson has a mass below the LEP2 lower limit of 114.4 GeV. If true, this suggests that the dominant Higgs decay is nonstandard while the production cross sections remain unmodified. We consider the possibility of nonstandard Higgs decays in the language of On-Shell Effective Theories (OSETs), and discuss a little considered class of Higgs decays, with a topology of both visible and missing energy. We study existing LEP constraints on such decays, and find that such decays would in general be allowed experimentally for ~ 100 GeV mass Higgses. Simple model realizations of these decays exist, which can occur in supersymmetric models and also in models with additional massive neutrinos. Some potential searches that can be performed at Tevatron and LHC, contained in standard supersymmetry topologies of leptons and missing energy, offer the possibility of discovering such Higgses.