Study of the decay<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msup><mml:mover accent="true"><mml:mi>B</mml:mi><mml:mo>¯</mml:mo></mml:mover><mml:mn>0</mml:mn></mml:msup><mml:mo>→</mml:mo><mml:msubsup><mml:mi>Λ</mml:mi><mml:mi>c</mml:mi><mml:mo>+</mml:mo></mml:msubsup><mml:mover accent="true"><mml:mi>p</mml:mi><mml:mo>¯</mml:mo></mml:mover><mml:msup><mml:mi>π</mml:mi><mml:mo>+</mml:mo></mml:msup><mml:msup><mml:mi>π</mml:mi><mml:mo>−</mml:mo></mml:msup></mml:math>and its intermediate states
Bibliographic record
Abstract
We study the decay ${\overline{B}}^{0}\ensuremath{\rightarrow}{\ensuremath{\Lambda}}_{c}^{+}\overline{p}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$, reconstructing the ${\ensuremath{\Lambda}}_{c}^{+}$ baryon in the $p{K}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}$ mode, using a data sample of $467\ifmmode\times\else\texttimes\fi{}{10}^{6}$ $B\overline{B}$ pairs collected with the BABAR detector at the PEP-II storage rings at SLAC. We measure branching fractions for decays with intermediate ${\ensuremath{\Sigma}}_{c}$ baryons to be $\mathcal{B}[{\overline{B}}^{0}\ensuremath{\rightarrow}{\ensuremath{\Sigma}}_{c}(2455{)}^{++}\overline{p}{\ensuremath{\pi}}^{\ensuremath{-}}]=(21.3\ifmmode\pm\else\textpm\fi{}1.0\ifmmode\pm\else\textpm\fi{}1.0\ifmmode\pm\else\textpm\fi{}5.5)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$, $\mathcal{B}[{\overline{B}}^{0}\ensuremath{\rightarrow}{\ensuremath{\Sigma}}_{c}(2520{)}^{++}\overline{p}{\ensuremath{\pi}}^{\ensuremath{-}}]=(11.5\ifmmode\pm\else\textpm\fi{}1.0\ifmmode\pm\else\textpm\fi{}0.5\ifmmode\pm\else\textpm\fi{}3.0)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$, $\mathcal{B}[{\overline{B}}^{0}\ensuremath{\rightarrow}{\ensuremath{\Sigma}}_{c}(2455{)}^{0}\overline{p}{\ensuremath{\pi}}^{+}]=(9.1\ifmmode\pm\else\textpm\fi{}0.7\ifmmode\pm\else\textpm\fi{}0.4\ifmmode\pm\else\textpm\fi{}2.4)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$, and $\mathcal{B}[{\overline{B}}^{0}\ensuremath{\rightarrow}{\ensuremath{\Sigma}}_{c}(2520{)}^{0}\overline{p}{\ensuremath{\pi}}^{+}]=(2.2\ifmmode\pm\else\textpm\fi{}0.7\ifmmode\pm\else\textpm\fi{}0.1\ifmmode\pm\else\textpm\fi{}0.6)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$, where the uncertainties are statistical, systematic, and due to the uncertainty on the ${\ensuremath{\Lambda}}_{c}^{+}\ensuremath{\rightarrow}p{K}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}$ branching fraction, respectively. For decays without ${\ensuremath{\Sigma}}_{c}(2455)$ or ${\ensuremath{\Sigma}}_{c}(2520)$ resonances, we measure $\mathcal{B}[{\overline{B}}^{0}\ensuremath{\rightarrow}{\ensuremath{\Lambda}}_{c}^{+}\overline{p}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}{]}_{\mathrm{non}\mathrm{\text{\ensuremath{-}}}{\ensuremath{\Sigma}}_{c}}=\phantom{\rule{0ex}{0ex}}(79\ifmmode\pm\else\textpm\fi{}4\ifmmode\pm\else\textpm\fi{}4\ifmmode\pm\else\textpm\fi{}20)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$. The total branching fraction is determined to be $\mathcal{B}[{\overline{B}}^{0}\ensuremath{\rightarrow}{\ensuremath{\Lambda}}_{c}^{+}\overline{p}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}{]}_{\mathrm{total}}=(123\ifmmode\pm\else\textpm\fi{}5\ifmmode\pm\else\textpm\fi{}7\ifmmode\pm\else\textpm\fi{}32)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$. We examine multibody mass combinations in the resonant three-particle ${\ensuremath{\Sigma}}_{c}\overline{p}\ensuremath{\pi}$ final states and in the four-particle ${\ensuremath{\Lambda}}_{c}^{+}\overline{p}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ final state, and observe different characteristics for the $\overline{p}\ensuremath{\pi}$ combination in neutral versus doubly charged ${\ensuremath{\Sigma}}_{c}$ decays.
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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 | 0.008 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.003 | 0.004 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.003 |
| Insufficient payload (model declined to judge) | 0.064 | 0.013 |
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".