Trilepton Signatures of Light Charged and CP-odd Higgs Bosons in Top Quark Decays
Enrico Lunghi (Indiana University)

In singlet extensions of the two Higgs doublet model, a light CP-odd Higgs boson (A) can significantly modify decay modes of the charged Higgs, without necessarily affecting decay modes of the standard model-like Higgs boson. These effects can be sizable even if the doublet component of the light CP-odd Higgs is small, so that constraints from Upsilon decays and direct CP-odd Higgs production do not apply. We study a scenario in which the charged Higgs is produced in top quark decays, t → H^±b, with dominant H^± → W^±A. We focus on the CP-odd Higgs mass range below the b ̄b threshold. We summarize all current experimental constraints and find that, as a result of H± → W^±A dominance, this scenario is not constrained in a large region of tanβ, mH^±, and CP-odd Higgs doublet component. We discuss search strategies based on A → τ^+τ^−, with both taus decaying leptonically, and on the subleading decay mode A → μ^+μ^−. We show thatasearchfort→H^+b, H^+ →W^+A, A→μ^+ μ^− in 20/fb of 8 TeV LHC data can constrain most of the currently allowed parameter space. Existing trilepton searches are not sensitive to this signal due to the adopted isolation criteria.