Observation of Exclusive Charmonium Production and<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>γ</mml:mi><mml:mi>γ</mml:mi><mml:mo>→</mml:mo><mml:msup><mml:mi>μ</mml:mi><mml:mo>+</mml:mo></mml:msup><mml:msup><mml:mi>μ</mml:mi><mml:mo>−</mml:mo></mml:msup></mml:math>in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>p</mml:mi><mml:mover accent="true"><mml:mi>p</mml:mi><mml:mo>¯</mml:mo></mml:mover></mml:math>Collisions at<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msqrt><mml:mi>s</mml:mi></mml:msqrt><mml:mo>=</mml:mo><mml:mn>1.96</mml:mn><mml:mtext> </mml:mtext><mml:mtext> </mml:mtext><mml:mi>TeV</mml:mi></mml:math>
Bibliographic record
Abstract
In CDF we have observed the reactions $p+\overline{p}\ensuremath{\rightarrow}p+X+\overline{p}$, with $X$ being a centrally produced $J/\ensuremath{\psi}$, $\ensuremath{\psi}(2S)$, or ${\ensuremath{\chi}}_{c0}$, and $\ensuremath{\gamma}\ensuremath{\gamma}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}$ in $p\overline{p}$ collisions at $\sqrt{s}=1.96\text{ }\text{ }\mathrm{TeV}$. The event signature requires two oppositely charged central muons, and either no other particles or one additional photon detected. Exclusive vector meson production is as expected for elastic photoproduction, $\ensuremath{\gamma}+p\ensuremath{\rightarrow}J/\ensuremath{\psi}\mathbf{(}\ensuremath{\psi}(2S)\mathbf{)}+p$, observed here for the first time in hadron-hadron collisions. We also observe exclusive ${\ensuremath{\chi}}_{c0}\ensuremath{\rightarrow}J/\ensuremath{\psi}+\ensuremath{\gamma}$. The cross sections $\frac{d\ensuremath{\sigma}}{dy}{|}_{y=0}$ for $J/\ensuremath{\psi}$, $\ensuremath{\psi}(2S)$, and ${\ensuremath{\chi}}_{c0}$ are $3.92\ifmmode\pm\else\textpm\fi{}0.25(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.52(\mathrm{syst})\text{ }\text{ }\mathrm{nb}$, $0.53\ifmmode\pm\else\textpm\fi{}0.09(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.10(\mathrm{syst})\text{ }\text{ }\mathrm{nb}$, and $76\ifmmode\pm\else\textpm\fi{}10(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}10(\mathrm{syst})\text{ }\text{ }\mathrm{nb}$, respectively, and the continuum is consistent with QED. We put an upper limit on the cross section for Odderon exchange in exclusive $J/\ensuremath{\psi}$ production.
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.036 | 0.005 |
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".