Measurement of the hadronic photon structure function F2 at LEP2
Bibliographic record
Abstract
The hadronic structure function of the photon F 2 γ ( x , Q 2 ) is measured as a function of Bjorken x and of the photon virtuality Q 2 using deep-inelastic scattering data taken by the OPAL detector at LEP at e + e − centre-of-mass energies from 183 to 209 GeV. Previous OPAL measurements of the x dependence of F 2 γ are extended to an average Q 2 of 〈 Q 2 〉=780 GeV 2 using data in the kinematic range 0.15< x <0.98. The Q 2 evolution of F 2 γ is studied for 12.1<〈 Q 2 〉<780 GeV 2 using three ranges of x . As predicted by QCD, the data show positive scaling violations in F 2 γ with F 2 γ (Q 2 )/α=(0.08 ± 0.02 +0.05 −0.03 )+(0.13 ± 0.01 +0.01 −0.01 ) ln Q 2 , where Q 2 is in GeV 2 , for the central x region 0.10–0.60. Several parameterisations of F 2 γ are in qualitative agreement with the measurements whereas the quark-parton model prediction fails to describe the data.
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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 | 0.002 |
| 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 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
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".