Decays of weak vector bosons andtquarks into doubly charged Higgs scalars

We evaluate the decays of $W^{+}$ and $Z^0$ bosons into ${\chi }^{++}$, 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 $M\left({\chi }^{++}\right)<\mathrm{}28\mathrm{}$ GeV, the branching fractions exceed 4% for $W^{+}\to {\chi }^{++}{\chi }^{-}$ and 2% for $Z^0\to {\chi }^{++}{\chi }^{--}$. Sequential ${\chi }^{++}\to l_1^{+}{l}_2^{+}$ leptonic decays could be substantially higher than previously recognized and could be dominant. Decay distributions for leptons of this origin are calculated for $\overline{p}p$ colliders. We also evaluate $t\to b{\chi }^{++}{\chi }^{-}$ decay.