Single neutral heavy lepton production at electron-muon colliders

New heavy Majorana and Dirac neutrinos production at future electron-muon colliders are investigated. The production of a single heavy neutrino is shown to be more relevant than pair production when comparing cross sections and neutrino mass ranges. The process $e^\pm \mu^\mp \longrightarrow {\nu} \ell^{\pm} W^{\mp}$ is studied including on-shell and off-shell heavy neutrino effects. Distributions are calculated including hadronization effects and experimental cuts that suppress background, in order to have a clear signal for heavy neutral leptons.