Measurements of time-dependent<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>asymmetries in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msup><mml:mi>B</mml:mi><mml:mn>0</mml:mn></mml:msup><mml:mo>→</mml:mo><mml:msup><mml:mi>D</mml:mi><mml:mrow><mml:mo stretchy="false">(</mml:mo><mml:mo>*</mml:mo><mml:mo stretchy="false">)</mml:mo><mml:mo>+</mml:mo></mml:mrow></mml:msup><mml:msup><mml:mi>D</mml:mi><mml:mrow><mml:mo stretchy="false">(</mml:mo><mml:mo>*</mml:mo><mml:mo stretchy="false">)</mml:mo><mml:mo>−</mml:mo></mml:mrow></mml:msup></mml:math>decays
Bibliographic record
Abstract
We present new measurements of time-dependent $CP$ asymmetries for ${B}^{0}\ensuremath{\rightarrow}{D}^{(*)+}{D}^{(*)\ensuremath{-}}$ decays using $(467\ifmmode\pm\else\textpm\fi{}5)\ifmmode\times\else\texttimes\fi{}{10}^{6}$ $B\overline{B}$ pairs collected with the BABAR detector located at the PEP-II $B$ Factory at the Stanford Linear Accelerator Center. We determine the $CP$-odd fraction of the ${B}^{0}\ensuremath{\rightarrow}{D}^{*+}{D}^{*\ensuremath{-}}$ decays to be ${R}_{\ensuremath{\perp}}=0.158\ifmmode\pm\else\textpm\fi{}0.028\ifmmode\pm\else\textpm\fi{}0.006$ and find $CP$ asymmetry parameters ${S}_{+}=\ensuremath{-}0.76\ifmmode\pm\else\textpm\fi{}0.16\ifmmode\pm\else\textpm\fi{}0.04$ and ${C}_{+}=+0.00\ifmmode\pm\else\textpm\fi{}0.12\ifmmode\pm\else\textpm\fi{}0.02$ for the $CP$-even component of this decay and ${S}_{\ensuremath{\perp}}=\ensuremath{-}1.80\ifmmode\pm\else\textpm\fi{}0.70\ifmmode\pm\else\textpm\fi{}0.16$ and ${C}_{\ensuremath{\perp}}=+0.41\ifmmode\pm\else\textpm\fi{}0.49\ifmmode\pm\else\textpm\fi{}0.08$ for the $CP$-odd component. We measure $S=\ensuremath{-}0.63\ifmmode\pm\else\textpm\fi{}0.36\ifmmode\pm\else\textpm\fi{}0.05$ and $C=\ensuremath{-}0.07\ifmmode\pm\else\textpm\fi{}0.23\ifmmode\pm\else\textpm\fi{}0.03$ for ${B}^{0}\ensuremath{\rightarrow}{D}^{+}{D}^{\ensuremath{-}}$, $S=\ensuremath{-}0.62\ifmmode\pm\else\textpm\fi{}0.21\ifmmode\pm\else\textpm\fi{}0.03$ and $C=+0.08\ifmmode\pm\else\textpm\fi{}0.17\ifmmode\pm\else\textpm\fi{}0.04$ for ${B}^{0}\ensuremath{\rightarrow}{D}^{*+}{D}^{\ensuremath{-}}$, and $S=\ensuremath{-}0.73\ifmmode\pm\else\textpm\fi{}0.23\ifmmode\pm\else\textpm\fi{}0.05$ and $C=+0.00\ifmmode\pm\else\textpm\fi{}0.17\ifmmode\pm\else\textpm\fi{}0.03$ for ${B}^{0}\ensuremath{\rightarrow}{D}^{+}{D}^{*\ensuremath{-}}$. For the ${B}^{0}\ensuremath{\rightarrow}{D}^{*\ifmmode\pm\else\textpm\fi{}}{D}^{\ensuremath{\mp}}$ decays, we also determine the $CP$-violating asymmetry $\mathcal{A}=+0.008\ifmmode\pm\else\textpm\fi{}0.048\ifmmode\pm\else\textpm\fi{}0.013$. In each case, the first uncertainty is statistical and the second is systematic. The measured values for the asymmetries are all consistent with the standard model.
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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 | 0.003 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.002 | 0.002 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.002 | 0.003 |
| Insufficient payload (model declined to judge) | 0.035 | 0.014 |
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".