Observation of the baryonic<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>B</mml:mi></mml:math>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>Λ</mml:mi><mml:mo>¯</mml:mo></mml:mover><mml:msup><mml:mi>K</mml:mi><mml:mo>−</mml:mo></mml:msup></mml:math>
Bibliographic record
Abstract
We report the observation of the baryonic $B$ decay ${\overline{B}}^{0}\ensuremath{\rightarrow}{\ensuremath{\Lambda}}_{c}^{+}\overline{\ensuremath{\Lambda}}{K}^{\ensuremath{-}}$ with a significance larger than 7 standard deviations based on $471\ifmmode\times\else\texttimes\fi{}{10}^{6}$ $B\overline{B}$ pairs collected with the BABAR detector at the PEP-II storage ring at SLAC. We measure the branching fraction for the decay ${\overline{B}}^{0}\ensuremath{\rightarrow}{\ensuremath{\Lambda}}_{c}^{+}\overline{\ensuremath{\Lambda}}{K}^{\ensuremath{-}}$ to be $(3.8\ifmmode\pm\else\textpm\fi{}{0.8}_{\mathrm{stat}}\ifmmode\pm\else\textpm\fi{}{0.2}_{\mathrm{sys}}\ifmmode\pm\else\textpm\fi{}{1.0}_{{\ensuremath{\Lambda}}_{c}^{+}})\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$. The uncertainties are statistical, systematic, and due to the uncertainty in the ${\ensuremath{\Lambda}}_{c}^{+}$ branching fraction. We find that the ${\ensuremath{\Lambda}}_{c}^{+}{K}^{\ensuremath{-}}$ invariant-mass distribution shows an enhancement above $3.5\text{ }\text{ }\mathrm{GeV}/{c}^{2}$.
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.001 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.028 | 0.008 |
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".