Measurements of the Higgs boson production, fiducial and differential cross-sections in the four lepton decay channel using 164 fb$^{-1}$ of data collected at $\sqrt{s}$ = 13.6 TeV with the ATLAS detector

TL;DR

This paper reports detailed measurements of Higgs boson production and decay in the four-lepton channel at 13.6 TeV using 164 fb$^{-1}$ of ATLAS data, confirming consistency with the Standard Model.

Contribution

First comprehensive differential and production-mode cross-section measurements of the Higgs boson at 13.6 TeV with ATLAS, including coupling and self-coupling analyses.

Findings

Measured inclusive fiducial cross-section of 3.65 fb, matching SM prediction.

Determined Higgs signal strength as μ = 0.99 ± 0.13.

Results align with Standard Model expectations.

Abstract

Inclusive, differential and production-mode cross-section measurements of the Higgs boson are performed in the $H \to ZZ^{*} \to 4\ell$ decay channel. The analysis uses proton-proton collision data produced at the Large Hadron Collider at a centre-of-mass energy of $\sqrt{s}=13.6$ TeV and recorded with the ATLAS detector, corresponding to an integrated luminosity of 164 fb$^{-1}$. The inclusive fiducial cross-section for the $H \to ZZ^{*} \to 4\ell$ process is measured to be $\sigma_{\textrm{fid}} = 3.65^{+0.35}_{-0.33}~\textrm{fb}$, in agreement with the Standard Model prediction of $\sigma_{\textrm{fid}}^{\textrm{SM}} = 3.68 \pm 0.17~\textrm{fb}$. 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 $\mu = 0.99 \pm 0.13$. The results are interpreted in terms of modifications of Higgs boson couplings using the $\kappa$ 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.