Measurement of the parity-odd angular distribution of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>γ</mml:mi></mml:math> rays from polarized neutron capture on <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mmultiscripts><mml:mi>Cl</mml:mi><mml:mprescripts/><mml:none/><mml:mn>35</mml:mn></mml:mmultiscripts></mml:math>
Bibliographic record
Abstract
We report a measurement of two energy-weighted $\ensuremath{\gamma}$ cascade angular distributions from polarized slow neutron capture on the $^{35}\mathrm{Cl}$ nucleus, one parity-odd correlation proportional to $\stackrel{P\vec}{{s}_{n}}\ifmmode\cdot\else\textperiodcentered\fi{}\stackrel{P\vec}{{k}_{\ensuremath{\gamma}}}$ and one parity-even correlation proportional to $\stackrel{P\vec}{{s}_{n}}\ifmmode\cdot\else\textperiodcentered\fi{}\stackrel{P\vec}{{k}_{n}}\ifmmode\times\else\texttimes\fi{}\stackrel{P\vec}{{k}_{\ensuremath{\gamma}}}$. A parity-violating asymmetry can appear in this reaction due to the weak nucleon-nucleon interaction, which mixes opposite parity S- and P-wave levels in the excited compound $^{36}\mathrm{Cl}$ nucleus formed upon slow neutron capture. If parity-violating (PV) and parity-conserving (PC) terms both exist, the measured differential cross section can be related to them via $\frac{d\ensuremath{\sigma}}{d\mathrm{\ensuremath{\Omega}}}\ensuremath{\propto}1+{A}_{\ensuremath{\gamma},\mathrm{PV}}cos\ensuremath{\theta}+{A}_{\ensuremath{\gamma},\mathrm{PC}}sin\ensuremath{\theta}$. The PV and PC asymmetries for energy-weighted $\ensuremath{\gamma}$ cascade angular distributions for polarized slow neutron capture on $^{35}\mathrm{Cl}$ averaged over the neutron energies from 2.27--9.53 meV were measured to be ${A}_{\ensuremath{\gamma},\mathrm{PV}}=(\ensuremath{-}23.9\ifmmode\pm\else\textpm\fi{}0.7)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$ and ${A}_{\ensuremath{\gamma},\mathrm{PC}}=(0.1\ifmmode\pm\else\textpm\fi{}0.7)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$. These results are consistent with previous experimental results. Systematic errors were quantified and shown to be small compared to the statistical error. These asymmetries in the angular distributions of the $\ensuremath{\gamma}$ rays emitted from the capture of polarized neutrons in $^{35}\mathrm{Cl}$ were used to verify the operation and data analysis procedures for the NPDGamma experiment, which measured the parity-odd asymmetry in the angular distribution of $\ensuremath{\gamma}$s from polarized slow neutron capture on protons.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.000 | 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 | 0.000 |
| Open science | 0.000 | 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".