First observation of a<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>Υ</mml:mi><mml:mn/><mml:mo>(</mml:mo><mml:mn>1</mml:mn><mml:mi>D</mml:mi><mml:mo>)</mml:mo><mml:mn/></mml:math>state
Bibliographic record
Abstract
We present the first evidence for the production of $\ensuremath{\Upsilon}(1D)$ states in the four-photon cascade, $\ensuremath{\Upsilon}(3S)\ensuremath{\rightarrow}\ensuremath{\gamma}{\ensuremath{\chi}}_{b}(2P),$ ${\ensuremath{\chi}}_{b}(2P)\ensuremath{\rightarrow}\ensuremath{\gamma}\ensuremath{\Upsilon}(1D),$ $\ensuremath{\Upsilon}(1D)\ensuremath{\rightarrow}\ensuremath{\gamma}{\ensuremath{\chi}}_{b}(1P),$ ${\ensuremath{\chi}}_{b}(1P)\ensuremath{\rightarrow}\ensuremath{\gamma}\ensuremath{\Upsilon}(1S),$ followed by the $\ensuremath{\Upsilon}(1S)$ annihilation into ${e}^{+}{e}^{\ensuremath{-}}$ or ${\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}.$ The signal has a significance of 10.2 standard deviations. The measured product branching ratio for these five decays, $(2.5\ifmmode\pm\else\textpm\fi{}0.5\ifmmode\pm\else\textpm\fi{}0.5)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5},$ is consistent with the theoretical estimates. The data are dominated by the production of one $\ensuremath{\Upsilon}(1D)$ state consistent with the $J=2$ assignment. Its mass is determined to be $(10161.1\ifmmode\pm\else\textpm\fi{}0.6\ifmmode\pm\else\textpm\fi{}1.6)$ MeV, which is consistent with the predictions from potential models and lattice QCD calculations. We also searched for $\ensuremath{\Upsilon}(3S)\ensuremath{\rightarrow}\ensuremath{\gamma}{\ensuremath{\chi}}_{b}(2P),$ ${\ensuremath{\chi}}_{b}(2P)\ensuremath{\rightarrow}\ensuremath{\gamma}\ensuremath{\Upsilon}(1D),$ followed by either $\ensuremath{\Upsilon}(1D)\ensuremath{\rightarrow}\ensuremath{\eta}\ensuremath{\Upsilon}(1S)$ or $\ensuremath{\Upsilon}(1D)\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}\ensuremath{\Upsilon}(1S).$ We find no evidence for such decays and set upper limits on the product branching ratios.
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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) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.002 |
| Research integrity | 0.002 | 0.002 |
| Insufficient payload (model declined to judge) | 0.020 | 0.002 |
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".