Unique Access to <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>u</mml:mi></mml:math>-Channel Physics: Exclusive Backward-Angle Omega Meson Electroproduction
Bibliographic record
Abstract
Backward-angle meson electroproduction above the resonance region, which was previously ignored, is anticipated to offer unique access to the three quark plus sea component of the nucleon wave function. In this Letter, we present the first complete separation of the four electromagnetic structure functions above the resonance region in exclusive $\ensuremath{\omega}$ electroproduction off the proton, $ep\ensuremath{\rightarrow}{e}^{\ensuremath{'}}p\ensuremath{\omega}$, at central ${Q}^{2}$ values of 1.60, $2.45\text{ }\text{ }{\mathrm{GeV}}^{2}$, at $W=2.21\text{ }\text{ }\mathrm{GeV}$. The results of our pioneering $\ensuremath{-}u\ensuremath{\approx}\ensuremath{-}{u}_{\mathrm{min}}$ study demonstrate the existence of a unanticipated backward-angle cross section peak and the feasibility of full $L/T/LT/TT$ separations in this never explored kinematic territory. At ${Q}^{2}=2.45\text{ }\text{ }{\mathrm{GeV}}^{2}$, the observed dominance of ${\ensuremath{\sigma}}_{T}$ over ${\ensuremath{\sigma}}_{L}$, is qualitatively consistent with the collinear QCD description in the near-backward regime, in which the scattering amplitude factorizes into a hard subprocess amplitude and baryon to meson transition distribution amplitudes: universal nonperturbative objects only accessible through backward-angle kinematics.
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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) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.002 | 0.003 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.003 | 0.003 |
| Open science | 0.002 | 0.002 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.815 | 0.707 |
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".