Study of<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>ρ</mml:mi><mml:mo>+</mml:mo></mml:msup><mml:msup><mml:mi>ρ</mml:mi><mml:mo>−</mml:mo></mml:msup></mml:math>decays and constraints on the CKM angle<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>α</mml:mi></mml:math>
Bibliographic record
Abstract
We present results from an analysis of ${B}^{0}\ensuremath{\rightarrow}{\ensuremath{\rho}}^{+}{\ensuremath{\rho}}^{\ensuremath{-}}$ decays using $(383.6\ifmmode\pm\else\textpm\fi{}4.2)\ifmmode\times\else\texttimes\fi{}{10}^{6}$ $B\overline{B}$ pairs collected by the BABAR detector at the PEP-II asymmetric-energy $B$ factory at SLAC. The measurements of the ${B}^{0}\ensuremath{\rightarrow}{\ensuremath{\rho}}^{+}{\ensuremath{\rho}}^{\ensuremath{-}}$ branching fraction, longitudinal polarization fraction ${f}_{L}$, and the $CP$-violating parameters ${S}_{\mathrm{long}}$ and ${C}_{\mathrm{long}}$ are as follows: $\mathcal{B}({B}^{0}\ensuremath{\rightarrow}{\ensuremath{\rho}}^{+}{\ensuremath{\rho}}^{\ensuremath{-}})=(25.5\ifmmode\pm\else\textpm\fi{}2.1(\mathrm{stat}{)}_{\ensuremath{-}3.9}^{+3.6}(\mathrm{syst}))\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$, ${f}_{L}=0.992\ifmmode\pm\else\textpm\fi{}0.024(\mathrm{stat}{)}_{\ensuremath{-}0.013}^{+0.026}(\mathrm{syst})$, ${S}_{\mathrm{long}}=\ensuremath{-}0.17\ifmmode\pm\else\textpm\fi{}0.20(\mathrm{stat}{)}_{\ensuremath{-}0.06}^{+0.05}(\mathrm{syst})$, ${C}_{\mathrm{long}}=0.01\ifmmode\pm\else\textpm\fi{}0.15(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.06(\mathrm{syst})$. We determine the unitarity triangle angle $\ensuremath{\alpha}$, using an isospin analysis of $B\ensuremath{\rightarrow}\ensuremath{\rho}\ensuremath{\rho}$ decays. One of the two solutions, $\ensuremath{\alpha}=[73.1,117.0]\ifmmode^\circ\else\textdegree\fi{}$ at 68% confidence level, is compatible with standard model-based fits of existing data. Constraints on the unitarity triangle are also evaluated using an $SU(3)$ symmetry-based approach.
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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 | 0.002 | 0.003 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.002 |
| Bibliometrics | 0.004 | 0.004 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.003 | 0.002 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.040 | 0.006 |
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".