Observation of the Bottomonium Ground State in the Decay<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>Υ</mml:mi><mml:mo stretchy="false">(</mml:mo><mml:mn>3</mml:mn><mml:mi>S</mml:mi><mml:mo stretchy="false">)</mml:mo><mml:mo>→</mml:mo><mml:mi>γ</mml:mi><mml:msub><mml:mi>η</mml:mi><mml:mi>b</mml:mi></mml:msub></mml:math>
Bibliographic record
Abstract
We report the results of a search for the bottomonium ground state ${\ensuremath{\eta}}_{b}(1S)$ in the photon energy spectrum with a sample of $(109\ifmmode\pm\else\textpm\fi{}1)$ million of $\ensuremath{\Upsilon}(3S)$ recorded at the $\ensuremath{\Upsilon}(3S)$ energy with the BABAR detector at the PEP-II $B$ factory at SLAC. We observe a peak in the photon energy spectrum at ${E}_{\ensuremath{\gamma}}={921.2}_{\ensuremath{-}2.8}^{+2.1}(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}2.4(\mathrm{syst})\text{ }\text{ }\mathrm{MeV}$ with a significance of 10 standard deviations. We interpret the observed peak as being due to monochromatic photons from the radiative transition $\ensuremath{\Upsilon}(3S)\ensuremath{\rightarrow}\ensuremath{\gamma}{\ensuremath{\eta}}_{b}(1S)$. This photon energy corresponds to an ${\ensuremath{\eta}}_{b}(1S)$ mass of ${9388.9}_{\ensuremath{-}2.3}^{+3.1}(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}2.7(\mathrm{syst})\text{ }\text{ }\mathrm{MeV}/{c}^{2}$. The hyperfine $\ensuremath{\Upsilon}(1S)$-${\ensuremath{\eta}}_{b}(1S)$ mass splitting is ${71.4}_{\ensuremath{-}3.1}^{+2.3}(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}2.7(\mathrm{syst})\text{ }\text{ }\mathrm{MeV}/{\mathrm{c}}^{2}$. The branching fraction for this radiative $\ensuremath{\Upsilon}(3S)$ decay is estimated to be $[4.8\ifmmode\pm\else\textpm\fi{}0.5(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}1.2(\mathrm{syst})]\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$.
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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 | 0.000 |
| 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 | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.004 | 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".