HEAVY MAJORANA NEUTRINOS AT EP COLLIDERS

Heavy Majorana neutrinos (N), predicted in various extensions of the s tandard model, are examined with respect to the present limits on thei r masses and mixings with ordinary leptons resulting in explicit examp les of allowed values of interest for present and planned accelerator energies. The decay N-->Zv is added to the previously available formal ism 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 s imulation. Signals in terms of isolated leptons and jets are found and shown to be effective in suppressing the dominating standard model ba ckgrounds. The discovery limits of such Majorana neutrinos are, for a mixing of 1%, about 160 GeV at HERA and 700 GeV at LEP + LHC.