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 distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.003 | 0.001 |
| Meta-epidemiology (narrow) | 0.002 | 0.004 |
| Meta-epidemiology (broad) | 0.001 | 0.005 |
| Bibliometrics | 0.001 | 0.003 |
| Science and technology studies | 0.004 | 0.005 |
| Scholarly communication | 0.002 | 0.003 |
| Open science | 0.005 | 0.004 |
| Research integrity | 0.002 | 0.004 |
| Insufficient payload (model declined to judge) | 0.020 | 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; both teacher heads agree on what is shown here.
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".