Parity Violation in pp and np Experiments
Bibliographic record
Abstract
Parity violation experiments involving only two nucleons provide a way to study the non‐leptonic, strangeness‐conserving part of the weak interaction in a clean measurement free of nuclear structure uncertainties. Such measurements are particularly appropriate for discussion at this conference as their success depends critically on the ability to accurately control and measure spin. Although simple in principle, the experiments are technically very demanding and great pains must be taken both in the preparation of the incident polarized beams and the measurement of the resultant parity violating asymmetries, which may be masked by a multitude of systematic effects. At low and intermediate energies, p⃗p experiments are sensitive to the medium range part of the parity violating nucleon‐nucleon force, usually parameterized in terms of rho and omega meson exchange. The pion does not contribute to parity violation in the pp experiments, as the π0 is its own antiparticle and parity violation would also imply CP violation. I review existing pp measurements with particular emphasis on the recent 221 MeV p⃗p measurement at TRIUMF which permitted the weak meson‐nucleon coupling constants hρpp and hωpp to be determined separately for the first time. The n⃗p experiments, on the other hand, are used to extract the weak pion nucleon coupling, fπ, describing the longest range part of the parity violating nucleon‐nucleon force. The np system is the only two nucleon system that is sensitive to fπ. I also review these experiments, with specific details of the n⃗p → dγ experiment now under preparation at Los Alamos National Laboratory.
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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".