Probing anomalous top-Higgs couplings at the HL-LHC via H→WW* decay channels

We study the prospects of probing the anomalous tHq (q = u, c) couplings via SS2L or 3L signatures at the High Luminosity (HL-LHC) run of the 14 TeV CERN collider. We focus on signals of the tH associated production followed by the decay modes t → bℓ+νℓ and H → WW*, and t t ¯ production followed by the decay modes t → bℓ+νℓ and t ¯ → H ( → W W ∗ ) q ¯ , where ℓ = e,μ. Based on two types of H → WW* decay topologies, one assuming the semileptonic decay mode H → WW*→ℓ+νjj and the other the fully leptonic decay mode H → W W ∗ → ℓ + ν ℓ − ν ¯ , we perform a full simulation for signals and backgrounds. It is shown that, at the future HL-LHC, the branching ratio Br(t → uh) (Br(t → ch)) can be probed to 1.17 (1.56) × 10−3 for the same-sign di-lepton channel, and to 7.1 × 10−4 (1.39 × 10−3) for the 3L channel at 3σ sensitivity.