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

Abstract

CMS and ATLAS have searched for a doubly-charged boson $H^{\pm \pm }$ which may arise from type II 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 $\Delta M\sim 1-40$ GeV which leads to enhanced pair-production cross-sections of $H^{\pm \pm }$ added by the gauge decays of the heavier neutral and singly-charged bosons. We reevaluate the constraints in the $\Delta M-M_{H^{++}}$ plane depending on the triplet vacuum expectation value $v_{\Delta }$ 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.

Comments: 15 pages, 13 figures