Measurements of ${\mathrm{t\bar{t}}\mathrm{H}} $ production and the CP structure of the Yukawa interaction between the Higgs boson and top quark in the diphoton decay channel

The first observation of the ${\mathrm{t\bar{t}}\mathrm{H}}$ process in a single Higgs boson decay channel with the full reconstruction of the final state (${\mathrm{H} \to \gamma\gamma} $) is presented, with a significance of 6.6 standard deviations ($\sigma$). The CP structure of Higgs boson couplings to fermions is measured, resulting in an exclusion of the pure CP-odd structure of the top Yukawa coupling at 3.2$\sigma$. The measurements are based on a sample of proton-proton collisions at a center-of-mass energy $\sqrt{s}=$ 13 TeV collected by the CMS detector at the LHC, corresponding to an integrated luminosity of 137 fb$^{-1}$. The cross section times branching fraction of the ${\mathrm{t\bar{t}}\mathrm{H}}$ process is measured to be ${\sigma_{{\mathrm{t\bar{t}}\mathrm{H}} } \mathcal{B}_{\gamma\gamma}}= $ 1.56$^{+0.34}_{-0.32}$ fb, which is compatible with the standard model prediction of 1.13$^{+0.08}_{-0.11}$ fb. The fractional contribution of the CP-odd component is measured to be ${f_{\mathrm{CP}}^{{\mathrm{H}\mathrm{t}\mathrm{t}} }} =$ 0.00 $\pm$ 0.33.The first observation of the tt¯H process in a single Higgs boson decay channel with the full reconstruction of the final state (H→γγ) is presented, with a significance of 6.6 standard deviations (σ). The CP structure of Higgs boson couplings to fermions is measured, resulting in an exclusion of the pure CP-odd structure of the top Yukawa coupling at 3.2σ. The measurements are based on a sample of proton-proton collisions at a center-of-mass energy s=13 TeV collected by the CMS detector at the LHC, corresponding to an integrated luminosity of 137 fb-1. The cross section times branching fraction of the tt¯H process is measured to be σtt¯HBγγ=1.56-0.32+0.34 fb, which is compatible with the standard model prediction of 1.13-0.11+0.08 fb. The fractional contribution of the CP-odd component is measured to be fCPHtt=0.00±0.33.The first observation of the $\mathrm{t\bar{t}}$H process in a single Higgs boson decay channel with the full reconstruction of the final state (H$\to\gamma\gamma$) is presented, with a significance of 6.6 standard deviations ($\sigma$). The CP structure of Higgs boson couplings to fermions is measured, resulting in an exclusion of the pure CP-odd structure of the top Yukawa coupling at 3.2$\sigma$. The measurements are based on a sample of proton-proton collisions at a center-of-mass energy $\sqrt{s} =$ 13 TeV collected by the CMS detector at the LHC, corresponding to an integrated luminosity of 137 fb$^{-1}$. The cross section times branching fraction of the $\mathrm{t\bar{t}}$H process is measured to be $\sigma_{\mathrm{t\bar{t}H}}\mathcal{B}_{\gamma\gamma} =$ 1.56 $^{+0.34}_{-0.32}$ fb, which is compatible with the standard model prediction of 1.13 $^{+0.08}_{-0.11}$ fb. The fractional contribution of the CP-odd component is measured to be $f^{\mathrm{Htt}}_\mathrm{CP} =$ 0.00 $\pm$ 0.33