The first observation of the $t\overline{t}H$ 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 $\sqrt{s}=13\mathrm{TeV}$ collected by the CMS detector at the LHC, corresponding to an integrated luminosity of $137{\mathrm{fb}}^{-1}$. The cross section times branching fraction of the $t\overline{t}H$ process is measured to be ${\sigma }_{t\overline{t}H}{\mathcal{B}}_{\gamma \gamma }={1.56}_{-0.32}^{+0.34}\mathrm{fb}$, which is compatible with the standard model prediction of ${1.13}_{-0.11}^{+0.08}\mathrm{fb}$. The fractional contribution of the $CP$-odd component is measured to be $f_{CP}^{Htt}=0.00\pm 0.33$.

中文翻译：

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双光子衰变通道中希格斯玻色子与顶夸克之间的余氢相互作用和余川相互作用的CP结构的测量。

第一次观察 $Ť\overline{Ť}H$ 在单个希格斯玻色子衰变通道中进行最后的状态完全重建的过程（$H\to \gamma \gamma$），具有6.6个标准偏差（$\sigma$）。的$CP$ 测量了希格斯玻色子与费米子的结构，从而排除了纯 $CP$顶部汤河联轴器的奇数结构 $3.2\sigma$。这些测量是基于质心能量处质子-质子碰撞的样本$\sqrt{s}=13\mathrm{电视}$ 由CMS检测器在大型强子对撞机上收集到的，对应于 $137{\mathrm{fb}}^{-\mathrm{1个}}$。横截面乘以$Ť\overline{Ť}H$ 过程被认为是 ${\sigma }_{Ť\overline{Ť}H}{\mathcal{乙}}_{\gamma \gamma }={1.56}_{-0.32}^{+0.34}\mathrm{fb}$，与的标准模型预测兼容 ${1.13}_{-0.11}^{+0.08}\mathrm{fb}$。的小部分贡献$CP$-奇分量被测量为 $F_{CP}^{HŤŤ}=0.00\pm 0.33$。