Three-body decays of heavy Dirac and Majorana fermions

Nonzero neutrino masses imply the existence of degrees freedom and interactions beyond those in Standard Model. A powerful indicator what these might be is nature massive neutrinos: Dirac fermions versus Majorana fermions. While addressing neutrinos often associated with searches for lepton-number violation, there are several other features that distinguish from Here, we compute great detail kinematics daughters decays into charged-leptons hypothetical heavy neutral leptons at rest. We allow decay to mediated by most general four-fermion interaction Lagrangian. demonstrate, example, when daughter have same flavor or detector insensitive their charges, polarized Majorana-fermion zero forward-backward asymmetry direction outgoing (relative parent spin), whereas Dirac-fermion can large asymmetries. Going studying asymmetries, also explore fully differential width three-body decays. It contains a wealth information not only about new but behind