Exotic seesaw-motivated heavy leptons at the LHC

We study the LHC potential for discovering TeV-scale SU(2)L 5-plet fermions introduced recently to explain small neutrino masses. We show that the Drell-Yan production and the decays of new exotic Σ leptons are testable at the LHC. Their production is abundant due to nontrivial electroweak gauge charges. For 1 fb^-1 of integrated luminosity at the present LHC √s=7 TeV, there can be 270 Σ-Σ pairs produced for M_Σ=400 GeV. Besides producing same-sign dilepton events, they could lead, due to a chosen small mixing between heavy and light leptons, to ~10 golden decays Σ⁺⁺⁺(Σ⁺⁺⁺)→W^±W^±l^± with a specific decay signature.