Measurement of the beam-normal single-spin asymmetry for elastic electron scattering from <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mmultiscripts><mml:mi mathvariant="normal">C</mml:mi><mml:mprescripts/><mml:none/><mml:mn>12</mml:mn></mml:mmultiscripts></mml:math> and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mmultiscripts><mml:mi>Al</mml:mi><mml:mprescripts/><mml:none/><mml:mn>27</mml:mn></mml:mmultiscripts></mml:math>
Bibliographic record
Abstract
We report measurements of the parity-conserving beam-normal single-spin elastic scattering asymmetries ${B}_{n}$ on $^{12}\mathrm{C}$ and $^{27}\mathrm{Al}$, obtained with an electron beam polarized transverse to its momentum direction. These measurements add an additional kinematic point to a series of previous measurements of ${B}_{n}$ on $^{12}\mathrm{C}$ and provide a first measurement on $^{27}\mathrm{Al}$. The experiment utilized the ${\mathrm{Q}}_{\mathrm{weak}}$ apparatus at Jefferson Lab with a beam energy of 1.158 GeV. The average laboratory scattering angle for both targets was $7.{7}^{\ensuremath{\circ}}$, and the average ${Q}^{2}$ for both targets was 0.024 37 ${\mathrm{GeV}}^{2}$ ($Q=0.1561$ GeV). The asymmetries are ${B}_{n}=\ensuremath{-}10.68\ifmmode\pm\else\textpm\fi{}0.90\phantom{\rule{0.222222em}{0ex}}(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.57\phantom{\rule{0.222222em}{0ex}}(\mathrm{syst})$ ppm for $^{12}\mathrm{C}$ and ${B}_{n}=\ensuremath{-}12.16\ifmmode\pm\else\textpm\fi{}0.58\phantom{\rule{0.222222em}{0ex}}(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.62\phantom{\rule{0.222222em}{0ex}}(\mathrm{syst})$ ppm for $^{27}\mathrm{Al}$. The results are consistent with theoretical predictions, and are compared to existing data. When scaled by $Z/A$, the $Q$ dependence of all the far-forward angle ($\ensuremath{\theta}<{10}^{\ensuremath{\circ}}$) data from $^{1}\mathrm{H}$ to $^{27}\mathrm{Al}$ can be described by the same slope out to $Q\ensuremath{\approx}0.35$ GeV. Larger-angle data from other experiments in the same $Q$ range are consistent with a slope about twice as steep.
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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 | 0.000 |
| 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 | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.007 | 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".