First Observation of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>C</mml:mi><mml:mi>P</mml:mi></mml:math>Violation in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow><mml:mover accent="true"><mml:mrow><mml:mi>B</mml:mi></mml:mrow><mml:mrow><mml:mo stretchy="false">¯</mml:mo></mml:mrow></mml:mover></mml:mrow><mml:mrow><mml:mn>0</mml:mn></mml:mrow></mml:msup><mml:mo stretchy="false">→</mml:mo><mml:msubsup><mml:mrow><mml:mi>D</mml:mi></mml:mrow><mml:mrow><mml:mi>C</mml:mi><mml:mi>P</mml:mi></mml:mrow><mml:mrow><mml:mo stretchy="false">(</mml:mo><mml:mo>*</mml:mo><mml:mo stretchy="false">)</mml:mo></mml:mrow></mml:msubsup><mml:msup><mml:mrow><mml:mi>h</mml:mi></mml:mrow><mml:mrow><mml:mn>0</mml:mn></mml:mrow></mml:msup></mml:mrow></mml:math>Decays by a Combined Time-Dependent Analysis of<i>BABAR</i>and Belle Data
Bibliographic record
Abstract
We report a measurement of the time-dependent $CP$ asymmetry of ${\overline{B}}^{0}\ensuremath{\rightarrow}{D}_{CP}^{(*)}{h}^{0}$ decays, where the light neutral hadron ${h}^{0}$ is a ${\ensuremath{\pi}}^{0}$, $\ensuremath{\eta}$, or $\ensuremath{\omega}$ meson, and the neutral $D$ meson is reconstructed in the $CP$ eigenstates ${K}^{+}{K}^{\ensuremath{-}}$, ${K}_{S}^{0}{\ensuremath{\pi}}^{0}$, or ${K}_{S}^{0}\ensuremath{\omega}$. The measurement is performed combining the final data samples collected at the $\mathrm{\ensuremath{\Upsilon}}(4S)$ resonance by the BABAR and Belle experiments at the asymmetric-energy $B$ factories PEP-II at SLAC and KEKB at KEK, respectively. The data samples contain $(471\ifmmode\pm\else\textpm\fi{}3)\ifmmode\times\else\texttimes\fi{}{10}^{6} B\overline{B}$ pairs recorded by the BABAR detector and $(772\ifmmode\pm\else\textpm\fi{}11)\ifmmode\times\else\texttimes\fi{}{10}^{6} B\overline{B}$ pairs recorded by the Belle detector. We measure the $CP$ asymmetry parameters $\ensuremath{-}{\ensuremath{\eta}}_{f}\mathcal{S}=+0.66\ifmmode\pm\else\textpm\fi{}0.10(\text{stat})\ifmmode\pm\else\textpm\fi{}0.06(\text{syst})$ and $\mathcal{C}=\ensuremath{-}0.02\ifmmode\pm\else\textpm\fi{}0.07(\text{stat})\ifmmode\pm\else\textpm\fi{}0.03(\text{syst})$. These results correspond to the first observation of $CP$ violation in ${\overline{B}}^{0}\ensuremath{\rightarrow}{D}_{CP}^{(*)}{h}^{0}$ decays. The hypothesis of no mixing-induced $CP$ violation is excluded in these decays at the level of 5.4 standard deviations.
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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 | 0.013 |
| Meta-epidemiology (narrow) | 0.002 | 0.002 |
| Meta-epidemiology (broad) | 0.001 | 0.002 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.004 | 0.002 |
| Scholarly communication | 0.006 | 0.011 |
| Open science | 0.003 | 0.006 |
| Research integrity | 0.003 | 0.010 |
| Insufficient payload (model declined to judge) | 0.188 | 0.103 |
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".