The first limit on invisible decays of $$B_s$$ mesons comes from LEP
Bibliographic record
Abstract
Abstract Motivated by the recent evidence for $$B^+\rightarrow K^+\bar{\nu } \nu $$ B + → K + ν ¯ ν decays at Belle II, we point out that fully invisible $$B_d$$ B d and $$B_s$$ B s meson decays are strongly constrained by LEP. A reinterpretation of an old inclusive ALEPH search for b-hadron decays with large missing energy allows us to place the limits $$\textrm{Br}(B_d \rightarrow \textrm{invisible}) < 1.4\times 10^{-4}$$ Br ( B d → invisible ) < 1.4 × 10 - 4 and $$\textrm{Br}(B_s \rightarrow \textrm{invisible}) < 5.6\times 10^{-4}$$ Br ( B s → invisible ) < 5.6 × 10 - 4 , both at $$90\%$$ 90 % CL. The $$B_d$$ B d limit is only a factor of 6 looser than the world-leading one provided by the BaBar collaboration, while the $$B_s$$ B s one is the first limit in the literature on this decay mode. These results are relevant in the context of new light states coupled to quarks and exemplify the power of a future Tera-Z factory at FCC-ee to look for B meson decays containing missing energy.
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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 | 0.003 | 0.009 |
| Meta-epidemiology (narrow) | 0.002 | 0.001 |
| Meta-epidemiology (broad) | 0.002 | 0.002 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.003 | 0.004 |
| Scholarly communication | 0.007 | 0.008 |
| Open science | 0.002 | 0.006 |
| Research integrity | 0.003 | 0.004 |
| Insufficient payload (model declined to judge) | 0.023 | 0.003 |
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".