Simultaneous Probe of the Charm and Bottom Quark Yukawa Couplings Using t$\overline{t}$H Events

A search for the standard model Higgs boson decaying to a charm quark-antiquark pair, 𝐻→𝑐⁢$\overline{𝑐}$, produced in association with a top quark-antiquark pair (t$\overline{t}$H) is presented. The search is performed with data from proton-proton collisions at $\sqrt{𝑠}$ =13  TeV, corresponding to an integrated luminosity of 138  fb$^{−1}$. Advanced machine learning techniques are employed for jet flavor identification and event classification. The Higgs boson decay to a bottom quark-antiquark pair is measured simultaneously and the observed t$\overline{t}$H⁢(𝐻→𝑏⁢$\overline{b}$) event rate relative to the standard model expectation is 0.91$^{+0.26}_{−0.22}$. The observed (expected) upper limit on the product of production cross section and branching fraction 𝜎⁡(t$\overline{t}$H)⁢ℬ⁡(𝐻→𝑐⁢$\overline{𝑐}$) is 0.11 (0.13) pb at 95% confidence level, corresponding to 7.8 (8.7) times the standard model prediction. When combined with the previous search for 𝐻 →𝑐⁢$\overline{𝑐}$ via associated production with a 𝑊 or 𝑍 boson, the observed (expected) 95% confidence interval on the Higgs-charm Yukawa coupling modifier, 𝜅$_𝑐$, is |𝜅$_𝑐$| <3.5 (2.7), the most stringent constraint to date.