Search for a doubly-charged boson in four-lepton final states in type II seesaw

CMS and ATLAS have searched for a doubly-charged H-+/-+/- boson which may arise from type 11 seesaw in the 7 TeV run at the LHC by considering pair or associated production of doubly-charged bosons under the assumption of degenerate triplet scalars. In this work, we consider non-degenerate triplet components with the mass gap Delta M similar to 1-40 GeV which leads to enhanced pair-production cross-sections of H-+/-+/- added by the gauge decays of the heavier neutral and singly-charged bosons. We reevaluate the constraints in the Delta M-MH++ plane ilepending on the triplet vacuum expectation value vb, in the type II seesaw model which are much more stringent than the current search limits. We further study the possibility of observing same-sign tetra-lepton signals in the allowed parameter space which can be probed in the future runs of the LHC. (C) 2013 The Authors. Published by Elsevier B.V. All rights reserved.