Combination of measurements of CP properties of Higgs boson interactions with vector bosons using proton-proton collisions at √s = 13 TeV with the ATLAS detector

A combination of measurements of the CP properties of Higgs boson interactions with electroweak gauge bosons is presented, using 140 fb⁻¹ of proton-proton collisions at √s = 13 TeV recorded by the ATLAS detector. Results from H→ττ, H→ WW*, H→γγ, H→ ZZ*, and WH,H→ bb̄ channels are combined. No evidence of CP violation is observed, and constrains on the CP-violating operators in the SMEFT framework are set in the Warsaw basis. The results from the combination improve by over 40% on previous individual limits on cHW̃ and, for the first time, simultaneous constraints on three coefficients cHW̃, cHB̃, and cHW̃B are set. This limits are the most stringent constraints to date on the relevant Wilson coefficients in the SMEFT framework with minimum model dependence.