Combined measurements of Higgs boson production and decay in the $H\rightarrow ZZ^∗\rightarrow4\ell$ and $H\rightarrow\gamma\gamma$ channels using $\sqrt{s}=$ 13 TeV pp collision data collected with the ATLAS experiment

Combined measurements of Higgs boson production cross sections and branching fractions are presented using the $H\rightarrow\gamma\gamma$ and $H\rightarrow ZZ^∗\rightarrow4\ell$ decay channels, based on 36.1 fb$^{−1}$ of proton–proton collision data recorded by the ATLAS experiment at the LHC at $\sqrt{s}=$ 13 TeV. Results are presented for the individual production processes of gluon fusion, vector-boson fusion, WH, ZH, and t$\bar{\rm{t}}$H , and for kinematic subdivisions of these processes. The total cross section for $pp \rightarrow H + X$ is determined to be $57.0^{+6.0}_{−5.9}$ (stat.) $^{+4.0}_{−3.3}$ (syst.) pb, consistent with the Standard Model prediction of $55.6^{+2.4}_{−3.4}$ pb. The results are translated into constraints on coefficients of Standard Model couplings. No significant deviations from the expectations are observed.