Neutral massive leptons in an SO(10) model with massless neutrinos

Abstract
The neutral massive leptons expected in SO(10) have been studied in a model which permits neutrinos to be massless. The mixing of these leptons with ordinary neutrinos introduces violations of weak universality. Three massive leptons occur: N1, coupling to μ and νμ with strength (0.026 GeVMN1) relative to the ordinary weak coupling; N2, coupling to τ and ντ with relative strength (1.8 GeVMN2); and N3, coupling to μ and νμ with relative strength (1.8 GeVMN3) and to τ and ντ with relative strength (8 GeVMN3). Their masses are bounded from below by 0.37, 6, and 25 GeV, respectively. The prospects for observing the neutral massive leptons in neutrino neutral-current interactions, in W and Z decays, and in τ, c, and b decays are discussed.