  The discovery of the Higgs boson suggests that also neutrinos get their mass
from spontaneous symmetry breaking. In the simplest ungauged lepton number
scheme, the Standard Model (SM) Higgs has now two other partners: a massive
CP-even, as well as the massless Nambu-Goldstone boson, called majoron. For
weak-scale breaking of lepton number the invisible decays of the CP- even Higgs
bosons to the majoron lead to potentially copious sources of events with large
missing energy. Using LHC results we study how the constraints on invisible
decays of the Higgs boson restrict the relevant parameters, substantially
extending those previously derived from LEP and shedding light on spontaneous
lepton number violation.
