Combined measurements of Higgs boson production and decay using up to $139$ fb$^{-1}$ of proton-proton collision data at $\sqrt{s}= 13$ TeV collected with the ATLAS experiment

A combination of measurements of Higgs boson production cross sections and branching fractions is presented. The combination is based on the analyses of the Higgs boson decay modes $H \to \gamma\gamma$, $ZZ^\ast$, $WW^\ast$, $\tau\tau$, $b\bar{b}$, $\mu\mu$, $Z\gamma$ and searches for decays into invisible final states using up to $139$ fb$^{-1}$ of proton--proton collision data collected at $\sqrt{s}= 13$ TeV with the ATLAS detector. Combined cross section measurements are presented for the gluon--gluon fusion (ggF) and vector-boson fusion (VBF) processes, and for associated production with vector bosons ($VH$) or top-quarks ($t\bar{t}H$, $tH$). Compared to the previous combined measurement, the $Z\gamma$ decay mode is included for the first time, together with a few additional production processes in the $b\bar{b}$ and $\tau\tau$ decay channels. In addition, several of the previous input measurements are updated to the full Run 2 data set. The global signal strength, defined as the measured Higgs boson signal yield normalised to its SM prediction, is determined to be $1.06 \pm 0.06$. Measurements in kinematic regions defined within the simplified template cross section framework are also reported. The results are interpreted in terms of modifiers applied to the Standard Model couplings of the Higgs boson to other particles, and are also used to set exclusion limits on parameters in the Standard Model Effective Field Theory framework and in several benchmark scenarios of the Two Higgs Doublet Model. No significant deviations from Standard Model predictions are observed.