TeV-scale seesaw mechanism catalyzed by the electron mass

We construct a model in which the neutrino Dirac mass terms are of order the electron mass and the seesaw mechanism proceeds via right-handed neutrinos with masses of order TeV. In our model the spectra of the three light and of the three heavy neutrinos are closely related. Since the mixing between light and heavy neutrinos is small, the model predicts no effects in pp and pp¯ colliders. Possible signatures of the model are the lepton-number-violating process e−e−→H−H−, where H− is a charged scalar particle, lepton-flavour-violating decays like μ−→e−e−e+, or a sizable contribution to the anomalous magnetic dipole moment of the muon.