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Measurement of off-shell Higgs boson production in the $H^*rightarrow ZZrightarrow 4ell$ decay channel using a neural simulation-based inference technique in 13 TeV $pp$ collisions with the ATLAS detector

ATLAS Collaboration - arXiv preprint arXiv:2412.01548, 2024 - arxiv.org
Physics paper hep-ex Suggest

… The data analysis is performed using a neural simulation-based inference method, which builds per-event likelihood ratios using neural networks. The observed (expected…

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BibTeX

@article{2412.01548v2,
Author        = { ATLAS Collaboration},
Title         = {Measurement of off-shell Higgs boson production in the $H^*\rightarrow
  ZZ\rightarrow 4\ell$ decay channel using a neural simulation-based inference
  technique in 13 TeV $pp$ collisions with the ATLAS detector},
Eprint        = {2412.01548v2},
DOI           = {10.1088/1361-6633/adcd9a},
ArchivePrefix = {arXiv},
PrimaryClass  = {hep-ex},
Abstract      = {A measurement of off-shell Higgs boson production in the $H^*\to ZZ\to 4\ell$
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
$0.87^{+0.75}_{-0.54}$ ($1.00^{+1.04}_{-0.95}$). 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 $4.3^{+2.7}_{-1.9}$
($4.1^{+3.5}_{-3.4}$) MeV.},
Year          = {2024},
Month         = {Dec},
Note          = {Rep. Prog. Phys. 88 (2025) 057803},
Url           = {http://arxiv.org/abs/2412.01548v2},
File          = {2412.01548v2.pdf}
}

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