UC Irvine

Inclusive, differential and production-mode cross-section measurements of the Higgs boson are performed in the H → ZZ* → 4ℓ decay channel. The analysis uses proton–proton collision data produced at the Large Hadron Collider at a centre-of-mass energy of s=13.6$$ \sqrt{s}=13.6 $$ TeV and recorded with the ATLAS detector, corresponding to an integrated luminosity of 164 fb−1. The inclusive fiducial cross-section for the H → ZZ* → 4ℓ process is measured to be σfid=3.65−0.33+0.35$$ {\sigma}_{\mathrm{fid}}={3.65}_{-0.33}^{+0.35} $$ fb, in agreement with the Standard Model prediction of σfidSM=3.68±0.17$$ {\sigma}_{\mathrm{fid}}^{\mathrm{SM}}=3.68\pm 0.17 $$ fb. Differential cross-sections are measured as a function of key kinematic observables of the Higgs boson and the four-lepton final state. Cross-sections are measured for the main production-modes in several exclusive regions of the Higgs boson production phase space and combined to measure an overall Higgs boson signal strength, defined as the measured cross-section normalised to the SM prediction, of μ = 0.99 ± 0.13. The results are interpreted in terms of modifications of Higgs boson couplings using the κ framework, within the Standard Model Effective Field Theory, and in scenarios probing the Higgs boson self-coupling. All the results are consistent with Standard Model expectations.