Search for a charged Higgs boson in pp collisions at √s = 8 TeV

A search for a charged Higgs boson is performed with a data sample corresponding to an integrated luminosity of 19.7 ± 0.5 fb−1 collected with the CMS detector in proton-proton collisions at s √ =8 ,TeV. The charged Higgs boson is searched for in top quark decays for m H± < m t − m b, and in the direct production pp → t(b)H± for m H± > m t − m b. The H± → τ ± ν τ and H± → tb decay modes in the final states τ h+jets, μτ h, ℓ+jets, and ℓℓ’ (ℓ =e, μ) are considered in the search. No signal is observed and 95% confidence level upper limits are set on the charged Higgs boson production. A model-independent upper limit on the product branching fraction B(t→H ± b)B(H ± →τ ± ν τ )=1.2−0.15% is obtained in the mass range m H± = 80–160 GeV, while the upper limit on the cross section times branching fraction σ(pp→t(b)H ± )B(H ± → τ ± ν τ )=0.38−0.025 pb is set in the mass range m H+ = 180–600 GeV. Here, σ(pp → t(b)H±) stands for the cross section sum σ(pp→t ¯ (b)H + )+σ(pp→t(b ¯ ¯ ¯ )H − ) . Assuming B(H ± →tb)=1 , an upper limit on σ(pp → t(b)H±) of 2.0–0.13 pb is set for m H± = 180–600 GeV. The combination of all considered decay modes and final states is used to set exclusion limits in the m H±−tan β parameter space in different MSSM benchmark scenarios.