Search for Axionlike Particles Produced in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msup><mml:mi>e</mml:mi><mml:mo>+</mml:mo></mml:msup><mml:msup><mml:mi>e</mml:mi><mml:mo>−</mml:mo></mml:msup></mml:math> Collisions at Belle II
Bibliographic record
Abstract
We present a search for the direct production of a light pseudoscalar $a$ decaying into two photons with the Belle II detector at the SuperKEKB collider. We search for the process ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}\ensuremath{\gamma}a$, $a\ensuremath{\rightarrow}\ensuremath{\gamma}\ensuremath{\gamma}$ in the mass range $0.2<{m}_{a}<9.7\text{ }\text{ }\mathrm{GeV}/{c}^{2}$ using data corresponding to an integrated luminosity of $(445\ifmmode\pm\else\textpm\fi{}3)\text{ }\text{ }{\mathrm{pb}}^{\ensuremath{-}1}$. Light pseudoscalars interacting predominantly with standard model gauge bosons (so-called axionlike particles or ALPs) are frequently postulated in extensions of the standard model. We find no evidence for ALPs and set 95% confidence level upper limits on the coupling strength ${g}_{a\ensuremath{\gamma}\ensuremath{\gamma}}$ of ALPs to photons at the level of ${10}^{\ensuremath{-}3}\text{ }\text{ }{\mathrm{GeV}}^{\ensuremath{-}1}$. The limits are the most restrictive to date for $0.2<{m}_{a}<1\text{ }\text{ }\mathrm{GeV}/{c}^{2}$.
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.010 | 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".