INVISIBLE HIGGS BOSONS AT PRESENT AND FUTURE COLLIDERS

In many extensions of the standard model the Higgs boson can have substantial invisible decay modes, for example, into light or massless weakly interacting Goldstone bosons associated to the spontaneous violation of lepton number below the weak scale. In this work, we first report on the model independent limits on the Higgs boson from the analysis of the present LEP samples after including the possibility of invisible decays and study the prospects for LEP II, Next, we review the detectability prospects for such invisible Higgs boson at the Next Linear Collider.