Precision measurements of Higgs hadronic decay modes at the FCC-ee

A bstract The expected precision at the FCC-ee on the product $$ \sigma \times \mathcal{B}\left(H\to b\overline{b},c\overline{c},s\overline{s}, gg\right) $$ σ × B H → b b ¯ c c ¯ s s ¯ gg of Higgs boson production cross sections times branching ratios of hadronic decays is presented. This study provides the first comprehensive determination of all major hadronic Higgs decay modes in a combined fit at future e + e − colliders, using both Higgs-strahlung ( ZH ) and Vector boson fusion ( $$ \nu \overline{\nu}H $$ ν ν ¯ H ) production processes, with a full treatment of interference effects in the $$ \nu \overline{\nu} jj $$ ν ν ¯ jj final state. It assumes four identical IDEA detectors collecting e + e − collisions at $$ \sqrt{s}=240 $$ s = 240 and 365 GeV. The combination of all channels across both energies, with full covariance between production and decay modes, yields a production cross-section times branching-ratio precision at the percent to per-mil level for the dominant hadronic final states ( $$ b\overline{b} $$ b b ¯ , $$ c\overline{c} $$ c c ¯ , gg ). These results provide a comprehensive input to the determination of Higgs coupling projections at the FCC-ee, and they establish for the first time sensitivity to the rare decay $$ H\to s\overline{s} $$ H → s s ¯ , demonstrating that FCC-ee has the potential to provide evidence of the strange-quark Yukawa coupling.