Consequences of models for monojet events from Z boson decay

Three models for monojet events with large missing transverse momentum observed at the CERN pp collider are studied: (i) Z decay into a neutral lepton pair where one of the pair decays within the detector while the other escapes, (ii) Z decay into two distinct neutral scalars where the lighter one is long lived, and (iii) Z decay into two distinct higgsinos where the lighter one is long lived. The first model necessarily gives observable decay in flight signals. Consequences of the latter two models are investigated in both pp collisions at CERN and e⁺e^- annihilation at PETRA/PEP energies.