Measurement of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>R</mml:mi><mml:mo mathvariant="bold">=</mml:mo><mml:mi mathvariant="bold-script">B</mml:mi><mml:mo mathvariant="bold" stretchy="false">(</mml:mo><mml:mi>t</mml:mi><mml:mo>→</mml:mo><mml:mi>W</mml:mi><mml:mi>b</mml:mi><mml:mo mathvariant="bold" stretchy="false">)</mml:mo><mml:mo>/</mml:mo><mml:mi mathvariant="bold-script">B</mml:mi><mml:mo mathvariant="bold" stretchy="false">(</mml:mo><mml:mi>t</mml:mi><mml:mo>→</mml:mo><mml:mi>W</mml:mi><mml:mi>q</mml:mi><mml:mo mathvariant="bold" stretchy="false">)</mml:mo></mml:math>in top-quark-pair decays using<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mtext mathvariant="normal">lepton</mml:mtext><mml:mo mathvariant="bold">+</mml:mo><mml:mtext mathvariant="normal">jets</mml:mtext></mml:math>events and the full CDF run II dataset
Bibliographic record
Abstract
We present a measurement of the ratio of the top-quark branching fractions $R=\mathcal{B}(t\ensuremath{\rightarrow}Wb)/\phantom{\rule{0ex}{0ex}}\mathcal{B}(t\ensuremath{\rightarrow}Wq)$, where $q$ represents quarks of type $b$, $s$, or $d$, in the final state with a lepton and hadronic jets. The measurement uses $\sqrt{s}=1.96\text{ }\text{ }\mathrm{TeV}$ proton-antiproton collision data from $8.7\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ of integrated luminosity collected with the Collider Detector at Fermilab during Run II of the Tevatron. We simultaneously measure $R=0.94\ifmmode\pm\else\textpm\fi{}0.09$ ($\mathrm{stat}+\mathrm{syst}$) and the $t\overline{t}$ production cross section ${\ensuremath{\sigma}}_{t\overline{t}}=7.5\ifmmode\pm\else\textpm\fi{}1.0\text{ }(\mathrm{stat}+\mathrm{syst})\text{ }\text{ }\mathrm{pb}$. The magnitude of the Cabibbo-Kobayashi-Maskawa matrix element, $|{V}_{\mathrm{tb}}|=0.97\ifmmode\pm\else\textpm\fi{}0.05$ ($\mathrm{stat}+\mathrm{syst}$) is extracted assuming three generations of quarks, and a lower limit of $|{V}_{\mathrm{tb}}|>0.89$ at 95% credibility level is set.
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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 | 0.003 | 0.016 |
| Meta-epidemiology (narrow) | 0.002 | 0.002 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.003 | 0.003 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.006 | 0.006 |
| Open science | 0.003 | 0.003 |
| Research integrity | 0.003 | 0.004 |
| Insufficient payload (model declined to judge) | 0.172 | 0.144 |
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".