Two-photon widths of the chi(cJ) states of charmonium
Bibliographic record
Abstract
Using a data sample of 24:5 Â 10 6 c ð2SÞ the reactions c ð2SÞ !cJ , cJ !have been studied for the first time to determine the two-photon widths of the cJ states of charmonium in their decay into two photons.The measured quantities are Bðc ð2SÞ !c0 Þ Â Bð c0 !Þ ¼ ð2:17 Æ 0:32 Æ 0:10Þ Â 10 À5 and Bðc ð2SÞ !c2 Þ Â Bð c2 !Þ ¼ ð2:68 Æ 0:28 Æ 0:15Þ Â 10 À5 .Using values for Bðc ð2SÞ !c0;c2 Þ and Àð c0;c2 Þ from the literature the two-photon widths are derived to be À ð c0 Þ ¼ ð2:36 Æ 0:35 Æ 0:22Þ keV, À ð c2 Þ ¼ ð0:66 Æ 0:07 Æ 0:06Þ keV, and R À ð c2 Þ=À ð c0 Þ ¼ 0:278 Æ 0:050 Æ 0:036.The importance of the measurement of R is emphasized.For the forbidden transition, c1 !, an upper limit of À ð c1 Þ < 0:03 keV is established.
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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 | 0.002 | 0.004 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.003 | 0.002 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.002 | 0.002 |
| Open science | 0.002 | 0.002 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.011 | 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".