Orateur
Description
A search for non-resonant hh production in the bbtt final state combines the full Run 2 dataset, corresponding to 140 fb^{-1} at √s = 13 TeV, with 56 fb^{-1} of early Run 3 data collected in 2022–2023 at √s = 13.6 TeV. Compared to the previous analysis in the same final state, the current analysis benefits from the additional integrated luminosity provided by the early Run 3 dataset, improved object reconstruction and identification algorithms, the introduction of online b-jet identification and its subsequent calibration, as well as several developments in the analysis strategy. This contribution focuses on the impact of online b-jet identification and its calibration on the analysis. Overall, these improvements result in an increased sensitivity to the hh signal. The measurement is compatible with the Standard Model expectation, with a best-fit signal strength of μₕₕ = 2.6^{+1.4}_{-1.0}. The observed (expected) significance of the hh signal relative to the background-only hypothesis reaches 2.6 (1.2) standard deviations, while the deviation from the Standard Model prediction amounts to 1.65 standard deviations. The same analysis is used to constrain the Higgs boson self-coupling. With the remaining Higgs boson couplings fixed to their Standard Model values, the observed (expected) 95% confidence-level interval is κ_λ ∈ [−3.4, 1.6] ∪ [5.5, 10.1] (κ_λ ∈ [−1.7, 8.5]). Finally, the analysis strategy is validated through measurements of Zh and ZZ production in the same final state. Their observed (expected) significances relative to the background-only hypothesis are 3.5 (2.4) and 1.8 (2.7) standard deviations, respectively.