Measurement of the H→γγH→γγ and H→ZZ∗→4ℓH→ZZ∗→4ℓ cross-sections in pp collisions at √s = 13.6 TeV with the ATLAS detector

The inclusive Higgs boson production cross-section is measured in the di-photon and the ZZ∗→4ℓZZ∗→4ℓ decay channels using 31.4 and 29.0 fb−1−1 of pp collision data respectively, collected with the ATLAS detector at a centre-of-mass energy of s=13.6s
​=13.6 TeVTeV. 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 σfid,γγ=σfid,γγ​= 76−13+1476−13+14​ fb, and σfid,4ℓ=σfid,4ℓ​= 2.80 ± 0.742.80±0.74 fb, in agreement with the corresponding Standard Model predictions of 67.6±3.767.6±3.7 fb and 3.67±0.193.67±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+12σ(pp→H)=67−11+12​ pb and 46±1246±12 pb at 13.6 TeVTeV from the di-photon and ZZ∗→4ℓZZ∗→4ℓ measurements respectively. The two measurements are combined into a total cross-section measurement of σ(pp→H)=58.2±8.7σ(pp→H)=58.2±8.7 pb, to be compared with the Standard Model prediction of σ(pp→H)SM=59.9±2.6σ(pp→H)SM​=59.9±2.6 pb.