Search for two body muon decay signals
Bibliographic record
Abstract
Lepton family number violation is tested by searching for ${\ensuremath{\mu}}^{+}\ensuremath{\rightarrow}{e}^{+}{X}^{0}$ decays among the $5.8\ifmmode\times\else\texttimes\fi{}{10}^{8}$ positive muon decay events analyzed by the TWIST collaboration. Limits are set on the production of both massless and massive ${X}^{0}$ bosons. The large angular acceptance of this experiment allows limits to be placed on anisotropic ${\ensuremath{\mu}}^{+}\ensuremath{\rightarrow}{e}^{+}{X}^{0}$ decays, which can arise from interactions violating both lepton flavor and parity conservation. Branching ratio limits of order ${10}^{\ensuremath{-}5}$ are obtained for bosons with masses of $13--80\text{ }\text{ }\mathrm{MeV}/{\mathrm{c}}^{2}$ and with different decay asymmetries. For bosons with masses less than $13\text{ }\text{ }\mathrm{MeV}/{\mathrm{c}}^{2}$ the asymmetry dependence is much stronger and the 90% limit on the branching ratio varies up to $5.8\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$. This is the first study that explicitly evaluates the limits for anisotropic two body muon 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 | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.007 | 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".