<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mmultiscripts> <mml:mi mathvariant="normal">He</mml:mi> <mml:mprescripts/> <mml:none/> <mml:mn>3</mml:mn> </mml:mmultiscripts> <mml:mo>(</mml:mo> <mml:mover accent="true"> <mml:mi>n</mml:mi> <mml:mo></mml:mo> </mml:mover> <mml:mo>,</mml:mo> <mml:mi>p</mml:mi> <mml:mo>)</mml:mo> <mml:mmultiscripts> <mml:mi mathvariant="normal">H</mml:mi> <mml:mprescripts/> <mml:none/> <mml:mrow> <mml:mn>3</mml:mn> </mml:mrow> </mml:mmultiscripts> </mml:math> parity-conserving asymmetry
Bibliographic record
Abstract
Recently, the $n^{3}\mathrm{He}$ Collaboration reported a measurement of the parity-violating (PV) proton directional asymmetry ${A}_{\mathrm{PV}}=[1.55\ifmmode\pm\else\textpm\fi{}0.97\phantom{\rule{0.16em}{0ex}}(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.24\phantom{\rule{0.16em}{0ex}}(\mathrm{sys})]\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}8}$ in the capture reaction of $^{3}\mathrm{He}(\stackrel{P\vec}{n},p)^{3}\mathrm{H}$ at meV incident neutron energies. The result increased the limited inventory of precisely measured and calculable PV observables in few-body systems required to further understand the structure of hadronic weak interaction. In this Letter, we report the experimental and theoretical investigation of a parity conserving (PC) asymmetry ${A}_{\mathrm{PC}}$ in the same reaction (the first ever measured PC observable at meV neutron energies). As a result of S- and P-wave mixing in the reaction, the ${A}_{\mathrm{PC}}$ is inversely proportional to the neutron wavelength $\ensuremath{\lambda}$. The experimental value is $(\ensuremath{\lambda}\ifmmode\times\else\texttimes\fi{}{A}_{\mathrm{PC}})\ensuremath{\equiv}\ensuremath{\beta}=[\ensuremath{-}1.97\ifmmode\pm\else\textpm\fi{}0.28\phantom{\rule{0.16em}{0ex}}(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.12\phantom{\rule{0.16em}{0ex}}(\mathrm{sys})]\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}\phantom{\rule{0.28em}{0ex}}\AA{}$. We present results for a theoretical analysis of this reaction by solving the four-body scattering problem within the hyperspherical harmonic method. We find that in the $^{3}\mathrm{He}(\stackrel{P\vec}{n},p)^{3}\mathrm{H}$ reaction, ${A}_{\mathrm{PC}}$ depends critically on the energy and width of the close ${0}^{\ensuremath{-}}$ resonant state of $^{4}\mathrm{He}$, resulting in a large sensitivity to the spin-orbit components of the nucleon-nucleon force and even to the three-nucleon force. The analysis of the accurately measured ${A}_{\mathrm{PC}}$ and ${A}_{\mathrm{PV}}$ using the same few-body theoretical models gives essential information needed to interpret the PV asymmetry in the $^{3}\mathrm{He}(\stackrel{P\vec}{n},p)^{3}\mathrm{H}$ reaction.
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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 | 0.003 | 0.003 |
| Meta-epidemiology (narrow) | 0.002 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.002 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.004 | 0.004 |
| Open science | 0.002 | 0.003 |
| Research integrity | 0.002 | 0.004 |
| Insufficient payload (model declined to judge) | 0.149 | 0.060 |
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".