YSF: ttH and tH production in multilepton channels with CMS experiment

We measure the CP structure of the Yukawa interaction between the Higgs boson ($\mathrm{H}$) and the top quark in a data sample enriched in the $\mathrm{t}\bar{\mathrm{t}}\mathrm{H}$ and $\mathrm{t}\mathrm{H}$ associated production. Using $138~\mathrm{fb}^{-1}$ of data collected in proton-proton collisions at $\sqrt{s}=$13 TeV by the CMS experiment at the CERN LHC, and targeting events where the H decays via via $\mathrm{H} \to \mathrm{W}\mathrm{W}$ or $\mathrm{H}\to\tau\tau$ and top quarks decay either leptonically or hadronically. We apply machine learning techniques to enhance the separation of CP-even from CP-odd scenarios. Two-dimensional confidence regions are set on $\kappa_{t}$ and $\widetilde{\kappa_{t}}$ which are the couplings of CP-even and CP-odd Lagrangian terms, respectively, of the top-Higgs Yukawa coupling. No significant fractional contributions, parameterized by the quantity $f_{CP}^{\mathrm{Htt}} $, are observed; the parameter is determined to be $f_{CP}^{\mathrm{Htt}} = 0.59$ with an interval of $(0.24, 0.81)$ at 68\% confidence level. The results are combined with previously published analyses covering the $\mathrm{H}\to\mathrm{Z}\mathrm{Z}$ and $\mathrm{H}\to\gamma\gamma$ decay modes, yielding two- and one-dimensional confidence regions on on $\kappa_{t}$ and $\widetilde{\kappa_{t}}$, while $f_{CP}^{\mathrm{Htt}} $ is determined to be $f_{CP}^{\mathrm{Htt}} = 0.28$ with an interval of $f_{CP}^{\mathrm{Htt}} <0.55$ at 68\% confidence level.