Doubly cvharged vector leptons and the Higgs portal
  Using a bottom up phenomenological approach we constructed a simple doubly charged vector lepton $E^{\pm\pm}$ model for the possible 750 GeV diphoton resonance $\Phi$ at the LHC assuming it to be a scalar particle. Since no stable doubly charged leptons are seen, to facilitate their decays we complete the model by adding a charged SM electroweak scalar $S^\pm$. $\Phi$ is a SM singlet and can be either an inert scalar or a Higgs field. In the inert case more than one vector lepton are required to account for the photon fusion production of the resonance if the model is to remain perturbative. For a Higgssed case $S^\pm$ can assist the production mechanism without using more than one such lepton. We also found that precision measurements constrain the couplings of $E^{\pm\pm}$ and $S^\pm$ to SM particles to be small. This raises the possibility that they can be fairly long lived and can give rise to displaced vertices if produced at the LHC. 
Wenjun Li and J.N.Ng
hep-ph