Production of doubly charged scalars from the decay of singly charged   scalars in the Higgs Triplet Model
  The existence of doubly charged Higgs bosons (H^{\pm\pm}) is a distinctive feature of the Higgs Triplet Model (HTM), in which neutrinos obtain tree-level masses from the vacuum expectation value of a neutral scalar in a triplet representation of SU(2)_L. We point out that a large branching ratio for the decay of a singly charged Higgs boson to a doubly charged Higgs boson via H^\pm\to H^{\pm\pm}W^* is possible in a sizeable parameter space of the HTM. From the production mechanism q'qbar\to W^* \to H^{\pm\pm}H^\mp the above decay mode would give rise to pair production of H^{\pm\pm}, with a cross section which can be comparable to that of the standard pair-production mechanism qqbar\to \gamma^*,Z^* \to H^{++}H^{--}. We suggest that the presence of a sizeable branching ratio for H^\pm\to H^{\pm\pm}W^* could significantly enhance the detection prospects of H^{\pm\pm} in the four-lepton channel. Moreover, the decays H^0\to H^\pm W^* and A^0\to H^\pm W^* from production of the neutral triplet scalars H^0 and A^0 would also provide an additional source of H^\pm, which can subsequently decay to H^{\pm\pm}. 
A.G. Akeroyd, Hiroaki Sugiyama
hep-ph