Measurements of decay branching fractions of ${{H \to b\bar b/c\bar c/gg}}$ in associated ${{(e^ + e^ - /\mu ^ +\mu ^- )H}}$ production at the CEPC

The high-precision measurement of Higgs boson properties is one of the primary goals of the Circular Electron Positron Collider (CEPC). The measurements of \begin{document}$H \to b\bar b/c\bar c/gg$\end{document} decay branching fraction in the CEPC experiment is presented, considering a scenario of analysing 5000 fb-1 \begin{document}$ e^+e^-$\end{document} collision data with the center-of-mass energy of 250 GeV. In this study the Higgs bosons are produced in association with a pair of leptons, dominantly mediated by the ZH production process. The statistical uncertainty of the signal cross section is estimated to be about 1% in the \begin{document}$H \to b\bar b$\end{document} final state, and approximately 5%-10% in the \begin{document}$H \to c\bar c/gg$\end{document} final states. In addition, the main sources of the systematic uncertainties and their impacts to the measurements of branching fractions are discussed. This study demonstrates the potential of precise measurement of the hadronic final states of the Higgs boson decay at the CEPC, and will provide key information to understand the Yukawa couplings between the Higgs boson and quarks, which are predicted to be the origin of quarks’ masses in the standard model.