Precision pion-proton elastic differential cross sections at energies spanning the Δ resonance
Bibliographic record
Abstract
A precision measurement of absolute ${\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}p$ elastic differential cross sections at incident pion laboratory kinetic energies from ${T}_{\ensuremath{\pi}}=141.15$ to 267.3 MeV is described. Data were obtained detecting the scattered pion and recoil proton in coincidence at 12 laboratory pion angles from $55\ifmmode^\circ\else\textdegree\fi{}$ to $155\ifmmode^\circ\else\textdegree\fi{}$ for ${\ensuremath{\pi}}^{+}p$ and six angles from $60\ifmmode^\circ\else\textdegree\fi{}$ to $155\ifmmode^\circ\else\textdegree\fi{}$ for ${\ensuremath{\pi}}^{\ensuremath{-}}p.$ Single arm measurements were also obtained for ${\ensuremath{\pi}}^{+}p$ energies up to 218.1 MeV, with the scattered ${\ensuremath{\pi}}^{+}$ detected at six angles from $20\ifmmode^\circ\else\textdegree\fi{}$ to $70\ifmmode^\circ\else\textdegree\fi{}.$ A flat-walled, supercooled liquid hydrogen target and solid ${\mathrm{CH}}_{2}$ targets were used. The data are characterized by small uncertainties, $\ensuremath{\sim}1--2%$ statistical and $\ensuremath{\sim}1--1.5%$ normalization. The reliability of the cross section results was ensured by carrying out the measurements under a variety of experimental conditions to identify and quantify the sources of instrumental uncertainty. Our lowest- and highest-energy data are consistent with overlapping results from TRIUMF and LAMPF. In general, the Virginia Polytechnic Institute SM95 partial-wave analysis (PWA) solution describes our data well, but the older Karlsruhe-Helsinki PWA solution KH80 does not.
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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 | 0.001 |
| 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 | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.006 | 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".