Measurement of the H → γγ and H → ZZ* → 4$\ell$ cross-sections in pp collisions at $\sqrt{s}$ = 13.6 TeV TeV with the ATLAS detector

The inclusive Higgs boson production cross-section is measured in the di-photon and the ZZ* → 4$\ell$ decay channels using 31.4 and 29.0 fb${}^{-1}$ of pp collision data respectively, collected with the ATLAS detector at a centre-of-mass energy of $\sqrt{s}$ = 13.6 TeV. To reduce the model dependence, the measurement in each channel is restricted to a particle-level phase space that closely matches the channel's detector-level kinematic selection, and it is corrected for detector effects. These measured fiducial cross-sections are σ${}_{fid,\gamma \gamma }$ = 76${}_{-13}^{+14}$ fb, and σ${}_{fid,4\ell }$ = 2.80 ± 0.74 fb, in agreement with the corresponding Standard Model predictions of 67.6 ± 3.7 fb and 3.67 ± 0.19 fb. Assuming Standard Model acceptances and branching fractions for the two channels, the fiducial measurements are extrapolated to the full phase space yielding total cross-sections of σ (pp → H) = 67${}_{-11}^{+12}$ pb and 46 ± 12 pb at 13.6 TeV from the di-photon and ZZ* → 4$\ell$ measurements respectively. The two measurements are combined into a total cross-section measurement of σ (pp → H)= 58.2 ± 8.7 pb, to be compared with the Standard Model prediction of σ (pp → H)${}_{SM}$ = 59.9 ± 2.6 pb.