Measurement of off-shell Higgs boson production in the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msup> <mml:mi>H</mml:mi> <mml:mo>∗</mml:mo> </mml:msup> <mml:mo>→</mml:mo> <mml:mi>Z</mml:mi> <mml:mi>Z</mml:mi> <mml:mo>→</mml:mo> <mml:mn>4</mml:mn> <mml:mi>ℓ</mml:mi> </mml:mrow> </mml:math> decay channel using a neural simulation-based inference technique in 13 TeV <i>pp</i> collisions with the ATLAS detector
Bibliographic record
Abstract
Abstract A measurement of off-shell Higgs boson production in the H ∗ → Z Z → 4 ℓ decay channel is presented. The measurement uses 140 fb −1 of proton–proton collisions at 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 Z Z → 4 ℓ 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 Z Z → 4 ℓ decay channel has an observed (expected) significance of 2.5 σ (1.3 σ ). 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 σ . When combined with the most recent ATLAS measurement in the Z Z → 2 ℓ 2 ν decay channel, the evidence for off-shell Higgs boson production has an observed (expected) significance of 3.7 σ (2.4 σ ). 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.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".