Heavy Majorana neutrinos in e − e − collisions 1 Christoph Greub

We discuss the process ee → WW mediated by heavy Majorana neutrino exchange in the t− and u channel. In our model the cross section for this reaction is a function of the masses (mN ) of the heavy Majorana neutrinos and mixing parameters (UeN ) originating from mixing between the ordinary left-handed standard model neutrinos and additional singlet right-handed neutrino fields. Taking into account the standard model background and contraints from low energy measurements, we present discovery limits in the (mN , U 2 eN) plane. We also discuss how to measure in principle the CP violating phases, i.e., the relative phases between the mixing parameters. (To be published in the Proceedings of the 1996 DPF/DPB Summer Study on New Directions for High Energy Physics (Snowmass 96).) Work supported in part by Schweizerischer Nationalfonds