HEAVY MAJORANA NEUTRINOS AT EP COLLIDERS

Heavy Majorana neutrinos (N), predicted in various extensions of the standard model, are examined with respect to the present limits on their masses and mixings with ordinary leptons resulting in explicit examples of allowed values of interest for present and planned accelerator energies. The decay N-->Zv is added to the previously available formalism and all dominating branching ratios are calculated. The production of Majorana neutrinos through charged current interactions in the ep colliders HERA and LEP + LHC is investigated using Monte Carlo event simulation. Signals in terms of isolated leptons and jets are found and shown to be effective in suppressing the dominating standard model backgrounds. The discovery limits of such Majorana neutrinos are, for a mixing of 1%, about 160 GeV at HERA and 700 GeV at LEP + LHC.