Measurement of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>W</mml:mi></mml:math>-boson polarization in top-quark decay using the full CDF Run II data set
Bibliographic record
Abstract
We measure the polarization of $W$ bosons from top-quark ($t$) decays into final states with a charged lepton and jets, $t\overline{t}\ensuremath{\rightarrow}{W}^{+}b{W}^{\ensuremath{-}}\overline{b}\ensuremath{\rightarrow}\ensuremath{\ell}\ensuremath{\nu}bq{\overline{q}}^{\ensuremath{'}}\overline{b}$, using the full Run II data set collected by the CDF II detector, corresponding to an integrated luminosity of $8.7\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$. A model-independent method simultaneously determines the fraction of longitudinal (${f}_{0}$) and right-handed (${f}_{+}$) $W$ bosons to yield ${f}_{0}=0.726\ifmmode\pm\else\textpm\fi{}0.066(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.067(\mathrm{syst})$ and ${f}_{+}=\ensuremath{-}0.045\ifmmode\pm\else\textpm\fi{}0.044(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.058(\mathrm{syst})$ with a correlation coefficient of $\ensuremath{-}0.69$. Additional results are presented under various standard model assumptions. No significant discrepancies with the standard model are observed.
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.004 | 0.001 |
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".