Direct search for the standard model Higgs boson decaying to a charm quark-antiquark pair

A search for $\text{H}\to \text{c}\bar{\text{c}}$ in associated VH production with leptonically decaying V (W or Z) boson is performed with $138\,\text{fb}^{-1}$ of proton-proton collisions at $\sqrt{s}=13\,\text{TeV}$ in the CMS experiment. Novel charm jet identification and analysis techniques are used. A search for $\text{Z}\to \text{c}\bar{\text{c}}$ in VZ events is used to validate the strategy and yields a first observation at a hadron collider with a significance of 5.7 standard deviations. The analysis yields $\sigma\left(\text{VH}\right)\mathcal{B}\left(\text{H}\to \text{c}\bar{\text{c}}\right)<0.94\,\text{pb}$ at $95\%$ CL. For $\kappa_{\text{c}}$, the Higgs-charm Yukawa coupling modifier, the observed $95\%$ CL interval (expected upper limit) is $1.1 <|\kappa_{\text{c}}|<5.5$ ($|\kappa_{\text{c}}|<3.4$) - the most stringent to date.