Measurement 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>-violating 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:mo stretchy="false">(</mml:mo><mml:mi>ρ</mml:mi><mml:mi>π</mml:mi><mml:msup><mml:mo stretchy="false">)</mml:mo><mml:mn>0</mml:mn></mml:msup></mml:math>decays using a time-dependent Dalitz plot analysis
Bibliographic record
Abstract
We present results for a time-dependent Dalitz plot measurement of $CP$-violating asymmetries in the mode ${B}^{0}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{0}$. The data set is derived from the complete sample of $471\ifmmode\times\else\texttimes\fi{}{10}^{6}$ $B\overline{B}$ meson pairs collected with the BABAR detector at the PEP-II asymmetric-energy ${e}^{+}{e}^{\ensuremath{-}}$ collider at the SLAC National Accelerator Laboratory operating on the $\ensuremath{\Upsilon}(4S)$ resonance. We extract parameters describing the time-dependent ${B}^{0}\ensuremath{\rightarrow}\ensuremath{\rho}\ensuremath{\pi}$ decay probabilities and $CP$ asymmetries, including $\mathcal{C}=0.016\ifmmode\pm\else\textpm\fi{}0.059\ifmmode\pm\else\textpm\fi{}0.036$, $\ensuremath{\Delta}\mathcal{C}=0.234\ifmmode\pm\else\textpm\fi{}0.061\ifmmode\pm\else\textpm\fi{}0.048$, $\mathcal{S}=0.053\ifmmode\pm\else\textpm\fi{}0.081\ifmmode\pm\else\textpm\fi{}0.034$, and $\ensuremath{\Delta}\mathcal{S}=0.054\ifmmode\pm\else\textpm\fi{}0.082\ifmmode\pm\else\textpm\fi{}0.039$, where the uncertainties are statistical and systematic, respectively. We perform a two-dimensional likelihood scan of the direct $CP$-violation asymmetry parameters for ${B}^{0}\ensuremath{\rightarrow}{\ensuremath{\rho}}^{\ifmmode\pm\else\textpm\fi{}}{\ensuremath{\pi}}^{\ensuremath{\mp}}$ decays, finding the change in ${\ensuremath{\chi}}^{2}$ between the minimum and the origin (corresponding to no direct $CP$ violation) to be $\ensuremath{\Delta}{\ensuremath{\chi}}^{2}=6.42$. We present information on the $CP$-violating parameter $\ensuremath{\alpha}$ in a likelihood scan that incorporates ${B}^{\ifmmode\pm\else\textpm\fi{}}\ensuremath{\rightarrow}\ensuremath{\rho}\ensuremath{\pi}$ measurements. To aid in the interpretation of our results, statistical robustness studies are performed to assess the reliability with which the true values of the physics parameters can be extracted. Significantly, these studies indicate that $\ensuremath{\alpha}$ cannot be reliably extracted with our current sample size, though the other physics parameters are robustly extracted.
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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 | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.010 | 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".