Low-energy test of second-class current in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>β</mml:mi></mml:math>decays of spin-aligned<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msup><mml:mrow/><mml:mn>20</mml:mn></mml:msup></mml:math>F and<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msup><mml:mrow/><mml:mn>20</mml:mn></mml:msup></mml:math>Na
Bibliographic record
Abstract
The $G$-parity-violating, second-class current- (SCC) induced tensor term in the weak-nucleon axial-vector current was determined from $\ensuremath{\beta}$-decay correlation measurements of the mass $A$ = 20 mirror pair. The alignment correlation terms in the $\ensuremath{\beta}$-decay angular distribution from the purely spin aligned mirror pair, ${}^{20}$F and ${}^{20}$Na, were measured in the present study. Combining the present results with existing results of $\ensuremath{\beta}$ and delayed $\ensuremath{\gamma}$-ray angular correlation measurements for the $A$ = 20 mirror pair, the SCC-induced tensor term was extracted to be ${d}_{\mathit{II}}/Ac$ = 0.18 $\ifmmode\pm\else\textpm\fi{}$ 0.48. In the extraction, the weak-magnetism term, $b/Ac$ = 8.58 $\ifmmode\pm\else\textpm\fi{}$ 0.28, evaluated from the $M$1 analog $\ensuremath{\gamma}$-ray decay strength, was used in a framework of the conserved vector current hypothesis. This is the first unambiguous extraction of the $(b\ensuremath{-}{d}_{\mathit{II}})/Ac$ term free from the contribution of the second-forbidden form factor, ${j}_{2}$, in the axial-vector current, which was a limiting factor for accurate determination of nonexistence of the SSC in the $\ensuremath{\beta}$ decay of the $A$ = 20 system.
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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 | 0.003 | 0.003 |
| Meta-epidemiology (narrow) | 0.004 | 0.005 |
| Meta-epidemiology (broad) | 0.003 | 0.006 |
| Bibliometrics | 0.001 | 0.003 |
| Science and technology studies | 0.003 | 0.005 |
| Scholarly communication | 0.002 | 0.004 |
| Open science | 0.006 | 0.008 |
| Research integrity | 0.003 | 0.005 |
| Insufficient payload (model declined to judge) | 0.002 | 0.006 |
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; both teacher heads agree on what is shown here.
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".