Search for $δ^{\pm\pm}$ with new decay patterns at the LHC

Abstract

A study of searching for doubly charged Higgs $(δ^{\pm \pm})$ is performed in two-Higgs-doublet extension of the conventional type-II seesaw model. We find that a fantastic mixing effect between singly charged Higgs of Higgs doublet and of triplet is arisen from the scalar potential. The mixing leads to following intriguing phenomena: (a) the mass splittings in triplet particles are magnified, (b) QCD processes dominate the production of $δ^{\pm \pm}$, and (c) new predominant decay channels of $δ^{\pm \pm}$ are $δ^{\pm \pm} \to W^{\pm^{[*]}} H^{\pm^{(*)}}_{1(2)}$, but not $δ^{\pm} \to (\ell^\pm \ell^\pm, W^\pm W^\pm)$ which are usually discussed in the literature. With luminosity of 40 fb$^{-1}$ and collision energy of 13 TeV, we demonstrate that $δ^{\pm \pm}$ with mass below $330$ GeV could be observed at the $5σ$ level. Moreover, when the luminosity approaches to 300 fb$^{-1}$, the observed mass of $δ^{\pm \pm}$ could reach up to 450 GeV.