A new avenue to charged Higgs discovery in multi-Higgs models

Current searches for the charged Higgs at the LHC focus only on the τν, cs, and tb final states. Instead, we consider the process pp → Θ → W^±H^± → W ⁺W^-A where Θ is a heavy neutral Higgs boson, H ^±is a charged Higgs boson, and A is a light Higgs boson, with mass either below or above the bb̄ threshold. The cross-section for this process is typically large when kinematically open since H^± → W^±A can be the dominant decay mode of the charged Higgs. The final state we consider has two leptons and missing energy from the doubly leptonic decay of the W⁺W^- and possibly additional jets; it is therefore constrained by existing SM Higgs searches in the W ⁺W^- channel. We extract these constraints on the cross-section for this process as a function of the masses of the particles involved. We also apply our results specifically to a type-II two Higgs doublet model with an extra Standard-Model-singlet and obtain new and powerful constraints on m_H^± and tan β. We point out that a slightly modified version of this search, with more dedicated cuts, could be used to possibly discover the charged Higgs, either with existing data or in the future.