Decays of weak vector bosons and t quarks into doubly charged Higgs scalars

We evaluate the decays of W⁺ and Z⁰ bosons into χ⁺⁺, the doubly charged member of the scalar triplet in the Gelmini-Roncadelli model in which spontaneously broken B-L symmetry gives Majorana masses to neutrinos. For M(χ⁺⁺)<28 GeV, the branching fractions exceed 4% for W⁺-->χ⁺⁺χ^- and 2% for Z⁰-->χ⁺⁺χ^--. Sequential χ⁺⁺-->l⁺₁l⁺₂ leptonic decays could be substantially higher than previously recognized and could be dominant. Decay distributions for leptons of this origin are calculated for p¯p colliders. We also evaluate t-->bχ⁺⁺χ^- decay.