Implications of a purely right-handed b-decay coupling

Abstract We examine the implications of the hypothesis that the decays of the bottom quark occur via pure right-handed couplings. We show that the existing lower limits on the lifetimes for neutrinoless double beta decay severely restrict the neutrino sector of the model and would be satisfied in a manner if there is either an L e − L μ or an L e − L τ symmetry in the model. We then show that the cosmological mass density constraints in combination with SN1987A observations imply lower bounds on the masses of the right-handed neutrinos of about 100 MeV (about 65 MeV if there are Goldstone bosons coupling to ν R 's) and also imply that the case of L e − L μ symmetry is consistent with data unless there are off-diagonal neutral currents involving the right-handed neutrinos.