We reanalyze the constraints imposed on lepton-number violating interactions by radiative contributions to neutrino masses at the one- and two-loop levels in supersymmetric models without R parity. The interactions considered are the ΔL=1 superpotential operators λ ijkLiLjEkc and λijk′LiQjDk c, and the ΔL=1 soft terms AijkL̃ iL̃jẼkc and A ijk′L̃iQ̃jD̃ kc. The two-loop contributions analyzed are those induced by the radiatively generated mass splitting between the CP-even and CP-odd sneutrino states. It is shown how the constraints on the couplings λijk and λijk′ coming from the one-loop analysis can be evaded. In such a case, the two-loop contributions to neutrino masses become important. The combined one- and two-loop analysis yields constraints on the couplings λi33 and λ i33′ that are rather difficult to escape. The two-loop analysis yields also constraints on Ai33 and Ai33′, which are not bounded at the one-loop level. More freedom remains for the couplings λijk, λijk′, and Aijk, Aijk′, when j and k are first- or second-generation indices.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)