INVISIBLE HIGGS BOSONS AT PRESENT AND FUTURE COLLIDERS

In many extensions of the standard model the Higgs boson can have subs tantial invisible decay modes, for example, into light or massless wea kly interacting Goldstone bosons associated to the spontaneous violati on of lepton number below the weak scale. In this work, we first repor t on the model independent limits on the Higgs boson from the analysis of the present LEP samples after including the possibility of invisib le decays and study the prospects for LEP II, Next, we review the dete ctability prospects for such invisible Higgs boson at the Next Linear Collider.