Measurement of parity-violating<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mi>γ</mml:mi></mml:mrow></mml:math>-ray asymmetry in the capture of polarized cold neutrons on protons
Why this work is in the frame
A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.
Bibliographic record
Abstract
The NPDGamma collaboration reports results from the first phase of a measurement of the parity violating up-down asymmetry ${A}_{\ensuremath{\gamma}}$ with respect to the neutron spin direction of $\ensuremath{\gamma}$ rays emitted in the reaction $\mathrm{nP\vec}+p\ensuremath{\rightarrow}d+\ensuremath{\gamma}$ using the capture of polarized cold neutrons on the protons in a liquid parahydrogen target. One expects parity-odd effects in the hadronic weak interaction between nucleons to be induced by the weak interaction between quarks. ${A}_{\ensuremath{\gamma}}$ in $\mathrm{nP\vec}+p\ensuremath{\rightarrow}d+\ensuremath{\gamma}$ is dominated by a $\ensuremath{\Delta}I=1$, ${}^{3}{S}_{1}$-${}^{3}{P}_{1}$ parity-odd transition amplitude in the n-p system. The first phase of the measurement was completed at the Los Alamos Neutron Science Center spallation source (LANSCE), with the result ${A}_{\ensuremath{\gamma}}=[\ensuremath{-}1.2\ifmmode\pm\else\textpm\fi{}2.1 (\mathrm{stat}.)\ifmmode\pm\else\textpm\fi{}0.2 (\mathrm{sys}.)]\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}7}$. We also report the first measurement of an upper limit for the parity-allowed left-right asymmetry in this reaction, with the result ${A}_{\ensuremath{\gamma},\mathrm{LR}}=[\ensuremath{-}1.8\ifmmode\pm\else\textpm\fi{}1.9 (\mathrm{stat}.)\ifmmode\pm\else\textpm\fi{}0.2 (\mathrm{sys}.)]\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}7}$. In this paper we give a detailed report on the theoretical background, experimental setup, measurements, extraction of parity-odd and parity-allowed asymmetries, analysis of potential systematic effects, and LANSCE results. The asymmetry has an estimated size of $5\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}8}$ and the aim of the NPDGamma collaboration is to measure it to $1\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}8}$. The second phase of the measurement will be performed at the Spallation Neutron Source at Oak Ridge National Laboratory.
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.
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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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 it