Majoron models and the Higgs boson search

If the SU(2)×U(1) model is extended by adding a complex singlet spin-zero field and a spontaneously broken global U(1) symmetry, a Higgs scalar can decay into a pair of Goldstone bosons. This decay could dominate over the conventional decay modes into fermion-antifermion pairs. In that case, the Higgs boson may escape detection in the standard search through ${\mathit{ZZ}}^{\mathrm{*}}$H coupling and hence could be lighter than implied by the CERN LEP data. Restrictions on the Higgs boson mass and other parameters of the model are derived using the data on the standard model Higgs boson search in the mass region 10–50 GeV.