Measurement of off-shell Higgs boson production in the $H^{\ast }\to ZZ\to 4\ell$ decay channel using a neural simulation-based inference technique in 13 TeV $pp$ collisions with the ATLAS detector

Abstract

A measurement of off-shell Higgs boson production in the $H^{\ast }\to ZZ\to 4\ell$ decay channel is presented. The measurement uses 140 fb${}^{-1}$ of proton-proton collisions at $\sqrt{s}=13$ TeV collected by the ATLAS detector at the Large Hadron Collider and supersedes the previous result in this decay channel using the same dataset. The data analysis is performed using a neural simulation-based inference method, which builds per-event likelihood ratios using neural networks. The observed (expected) off-shell Higgs boson production signal strength in the $ZZ\to 4\ell$ decay channel at 68% CL is $0.87_{-0.54}^{+0.75}$ ($1.00_{-0.95}^{+1.04}$). The evidence for off-shell Higgs boson production using the $ZZ\to 4\ell$ decay channel has an observed (expected) significance of $2.5\sigma$ ($1.3\sigma$). The expected result represents a significant improvement relative to that of the previous analysis of the same dataset, which obtained an expected significance of $0.5\sigma$. When combined with the most recent ATLAS measurement in the $ZZ\to 2\ell 2\nu$ decay channel, the evidence for off-shell Higgs boson production has an observed (expected) significance of $3.7\sigma$ ($2.4\sigma$). The off-shell measurements are combined with the measurement of on-shell Higgs boson production to obtain constraints on the Higgs boson total width. The observed (expected) value of the Higgs boson width at 68% CL is $4.3_{-1.9}^{+2.7}$ ($4.1_{-3.4}^{+3.5}$) MeV.

65 pages in total, author list starting page 48, 22 figures, 9 tables, published in Rep. Prog. Phys. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HIGP-2024-14

References in corpus (29)

• Observation of a new particle in the search for the Standard Model Higgs boson with the ATLAS detector at the LHC
• Observation of a new boson at a mass of 125 GeV with the CMS experiment at the LHC
• The automated computation of tree-level and next-to-leading order differential cross sections, and their matching to parton shower simulations
• An Introduction to PYTHIA 8.2
• An NNLO subtraction formalism in hadron collisions and its application to Higgs boson production at the LHC
• Higgs boson gluon-fusion production in N3LO QCD
• A portrait of the Higgs boson by the CMS experiment ten years after the discovery
• A detailed map of Higgs boson interactions by the ATLAS experiment ten years after the discovery
• Muon reconstruction and identification efficiency in ATLAS using the full Run 2 $pp$ collision data set at $\sqrt{s}=13$ TeV
• Jet energy scale and resolution measured in proton-proton collisions at $\sqrt{s}=13$ TeV with the ATLAS detector
• Performance of the ATLAS muon triggers in Run 2
• Luminosity determination in $pp$ collisions at $\sqrt{s}=13$ TeV using the ATLAS detector at the LHC
• A measurement of the Higgs boson mass in the diphoton decay channel
• Measurements of the Higgs boson width and anomalous HVV couplings from on-shell and off-shell production in the four-lepton final state
• Higgs boson production cross-section measurements and their EFT interpretation in the $4\ell$ decay channel at $\sqrt{s}$ = 13 TeV with the ATLAS detector
• Taming the off-shell Higgs boson
• Next-to-leading-order electroweak corrections to the production of four charged leptons at the LHC
• Measurement of the Higgs boson width and evidence of its off-shell contributions to ZZ production
• Software and computing for Run 3 of the ATLAS experiment at the LHC
• The ATLAS Inner Detector Trigger performance in pp collisions at 13 TeV during LHC Run 2
• Combined measurement of the Higgs boson mass from the $H\to \gamma \gamma$ and $H\to Z{Z}^{\ast }\to 4\ell$ decay channels with the ATLAS detector using $\sqrt{s}$ = 7, 8 and 13 TeV $pp$ collision data
• Electron and photon efficiencies in LHC Run 2 with the ATLAS experiment
• Evidence of off-shell Higgs boson production from $ZZ$ leptonic decay channels and constraints on its total width with the ATLAS detector
• Learning Likelihood Ratios with Neural Network Classifiers
• Measurement of the Higgs boson mass in the $H\to Z{Z}^{\ast }\to 4\ell$ decay channel using 139 fb${}^{-1}$ of $\sqrt{s}=13$ TeV $pp$ collisions recorded by the ATLAS detector at the LHC
• Operational Experience and R&D results using the Google Cloud for High Energy Physics in the ATLAS experiment
• Total cost of ownership and evaluation of Google cloud resources for the ATLAS experiment at the LHC
• Constraint on the total width of the Higgs boson from Higgs boson and four-top-quark measurements in $pp$ collisions at $\sqrt{s}$ = 13 TeV with the ATLAS detector
• Constraints on standard model effective field theory for a Higgs boson produced in association with W or Z bosons in the H $\to \mathrm{b}\bar{\mathrm{b}}$ decay channel in proton-proton collisions at $\sqrt{s}$ = 13 TeV

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• Logarithmically-accurate and positive-definite NLO shower matching
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• Constraining off-shell Higgs boson production and the Higgs boson total width using $WW\to \ell \nu \ell \nu$ final states with the ATLAS detector
• Data-Driven High-Dimensional Statistical Inference with Generative Models
• Exploring the BSM parameter space with Neural Network aided Simulation-Based Inference
• Strong CWoLa: Binary Classification Without Background Simulation
• Theoretical modeling of QCD radiation in off-shell Higgs production through gluon fusion
• Measurement of the Higgs boson total decay width using the H $\to$ WW $\to$ e$\nu \mu \nu$ decay channel in proton-proton collisions at $\sqrt{s}$ = 13 TeV