IV.P186 — beta-Decay nu/nu-bar as Helicity Labels (not particle/antiparticle)

In beta^- decay (n->p+e^-+nu_bar_e), the nu_bar_e label means right-handed Majorana neutrino (past-directed tau^1). In beta^+ decay (p->n+e^++nu_e), nu_e is the same particle with left-handed helicity (future-directed tau^1). The overbar is a helicity label, not a particle/antiparticle distinction. Lepton number L is not a gauge charge in Category tau (not associated with any of the 5 generators). L is broken by Majorana neutrino masses by 2 units per interaction.