Measurement of the proton’s G[sub Ep]/G[sub Mp] ratio to Q[sup 2]=5.6 GeV[sup 2] at JLab
Bibliographic record
Abstract
The ratio of the electric and magnetic proton form factors, GEp/GMp, has been studied in the Thomas Jefferson National Accelerator Facility (Hall) A at JLab in two experiments, from measurements of the longitudinal and transverse polarization of the recoil proton, Pl and Pt, respectively, in the elastic scattering of polarized electrons, e⃗p→ep⃗. Together, these experiments cover the Q2-range 0.5 to 5.6 GeV2. The results of the second experiment are discussed here; although preliminary, they confirm and extend the finding of the first experiment, that the ratio μpGEp/GMp, which is close to 1 for Q2<0.8 GeV2, decreases approximately linearly with Q2 above this momentum transfer squared, and reaches a value ∼0.19 at Q2=5.6 GeV2. The new results presented here have been obtained by measuring the recoil proton polarization in e⃗p→ep⃗, which provides a better way to obtain GEp, even in the presence of a dominant magnetic form factor. Precision measurements of polarization observables have become possible with the advent of polarized electron beams with ≈100% duty factor, high current and high polarization.
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".